GSO RC images 21 May 2009

[Paul Haese]

Well got most of the things sorted with the GSO RC. Focusor works great, holds collimation and the guiding is working nicely. I did have to up the aggression a little to get it right for the focal length.

I reckon these scopes are going to take off.

The only thing I am not happy with is the star bloom in the images. Any advice on this would be greatly appreciated.

NGC5128 (http://paulhaese.net/NGC5128closeup.html)

Eta Carina (http://paulhaese.net/EtaCarinacloseup.html)

Trifid (M20) (http://paulhaese.net/trifidcloseup.html)

comments welcome.

BTW these images are reasonably large, dial up users might have to wait a little while.

[Terry B]

What do you mean by "blooming"?
Blooming is leakage across the pixels when they saturate. I think you mostly have scattering which is probably more from the actual scope and the spider.

[troypiggo]

Excellent results. Are you using a flattener or was it a collimation thing that was causing the elongated stars initially?

[gbeal]

Stunning Paul, simply stunning, especially 5128.

[Tamtarn]

Three great images there Paul.

Looks like you are on a winner with the RC, you should be pretty happy with the nice sharp detail in these images.

[Paul Haese]

Terry, that is what I mean, I think the 40D has problems with light leakage across the pixels. I am sure if I had a dedicated Astro camera the bloated stars would be less of an issue.

Troy I am using the Tak flattener, the collimation with the previous focusor was an issue. Not present at all now.

Thanks Gary, yep I am very impressed with this telescope myself. Not hand picked, just given what was on the shelf. If you have got the money get one before they go up in price.

[Paul Haese]

Thanks David and Barb, really like the scope.

[AlexN]

Hats off to you.. Lovely, 5128 and eta are stunners!

Alex.

[acropolite]

Nice work Paul, looks like a nice new toy, I can't remember whether it was you who said it but I seem to remember some comment about flex in the focusser did you overcome that or replace the focusser?

[Paul Haese]

Phil, yeah it was me and perhaps a few of the other guys. I got a Feather Touch and this sorted the issue out. No more flex and the images look flat, mind you CCD inspector says otherwise.

Thanks Alex.

[Quark]

Lovely images Paul,

You must be really stoked with this result.
All the more satisfying due to working through the initial teething problems.

All of these images look great , your 5128 compares very well with David Malins in his book "The Invisible Universe", cannot find any detail in his that is not in yours.

Well done
Regards
Trevor

[Paul Haese]

Thanks Trevor,yep very happy but of course there is always more ways of improving upon the data collection and processing.

While the 5128 might compare well with David Malins image, it is still a far cry from one posted by Peter Ward. I guess the extra aperture and STL11000 certainly makes a significant difference, and maybe that extra 20,000 dollars gives you that final crispness to the image. Still beggars cannot be choosers.

[Peter Ward]

Nice work. All the basics have been covered very well. Beautifully focused,
well guided, good S/N ratio.

The only meaningful step up from here is, as you hinted, tri-colour with a dedicated astro CCD.

Well done:thumbsup:

[gregbradley]

Hi Paul,

They are very high quality images and at the top of DSLR images I have seen.

As far as blooming goes, there is very little of a halo around the brighter stars. You can get that with any camera. Try lassoing the bright stars you would like to look sharper and use a small amount of minimum filter on them.

Or overall use some deconvolution but not overdo it.

To me though those stars don't attract my attention at all and perfectly acceptable.

So much for the guy who said you'd get blobby stars. He should be regretting opening his mouth so wide now.

I guess what he doesn't understand is modern China isn't a bunch of guys in some grotty factory rough hand polishing mirrors. I bet they have the latest gear and it turns out the same quality mirror after mirror and its all computer controlled.

Greg.

[Paul Haese]

Thanks for the advice Guys.

Peter, you know which one I want, but cannot afford yet.;)

Greg, I will give that a try with the lasso. Thanks for the tips.

[Peter Ward]

You really have got some excellent results, which are frankly better than many of the dedicated astro-ccd images out there.

As I said, the basics need to be covered, collimation, focus, focus, focus, mount alignment, tracking & guiding....and you've done all of that very well!

Telescopes, cameras, cars, hi-fi's are all very similar, in that the first 80% can be got without fancy engineering or undue cost. With some intelligent tweaks (eg $A500 Taka flattener), a skilled user can maybe squeeze another 10% .

Things tend to get a little exponential in engineering and cost after that.... and for many that last little bit of resolution or S/N is simply not perceptible, or desired given the often significant cost.

[bloodhound31]

Paul, these are amazing mate. I don't have a favorite, as they are all stunning!

Oh how I wish I had a RC.....

Baz.

[TrevorW]

Paul look at the date you posted on the title line

Cheers

[Paul Haese]

Oops, wrong date. Perhaps a mod can fix the date for me. It should read 2009. Half way through the year and I am still not with it. LOL

[RB]

I fixed it Paul.

[RB]

...and now that I've had a look at the images, my congratulations to you.
Very sharp with heaps of detail, colours well saturated, you've done a great job indeed.

:thumbsup:

[gregbradley]

Looks to me like some Chinese Telescope makers are going to be the new Takahashi in the not too distant future and will shake up the lucrative Ritchey Chretien world.

Greg.

[Paul Haese]

Thank Andrew for the fix up and for the praise.

Greg, you know that might be a real possibility and the bottom line is that we might get good prices on telescopes for some time.

[gregbradley]

I ran your image through some Photoshop actions and steps and the stars shrunk easily. My version may be slightly oversharpened but if you want a link to see how the stars came out I can post it for you.

Greg.

[Paul Haese]

Absolutely and then tell me the action step by step, thanks mate.

[gregbradley]

OK here it is- I redid it to reduce the amount of sharpening. Total time to process was about 4 minutes;

http://upload.pbase.com/image/112821714


1. Noel Carboni Photoshop action "increase star colour" one time through.

2. Noel Carboni Photoshop action "reduce star size" one time through.

3. Selective sharpening:

a) duplicate layer
b) set to "overlay" mode
c) filters/other/high pass 2.5 pixels enter
d) layer/layer mask/hide all
e) select brush tool, foreground tool set to white and black with white on top
f) rub over areas you want sharpened in this case only the galaxy dust band and nowhere else
g) layer/flatten image

Thats it.

Greg.

[gregbradley]

Also Paul to put it in perspective I think your image is quite a bit better than this image I took about 1.5 years ago with an RCOS 12.5 inch, Tak reducer (I think or it may have been native F9) and STL11000M class 2 camera with Astrodon filters and 3:45 total exposure:

http://www.pbase.com/gregbradley/image/96619186

Not to say the RCOS 12.5 was being used to its maximum by me but that is from my dark site which I know has awesome super dark and stable (mostly) skies.

Greg.

[dpastern]

Super set Paul, I'll eat my words, that RC is looking very nice. Worrying is the internal reflections, but I'm sure that'll get sorted out. I tell you what, I might just save for a 12" version of this baby ;-)

Dave

[gregbradley]

What's the problem with internal reflections? Was that from an earlier post?

They could be sorted pretty easily as handling reflections would be simply:

1. More baffling
2. Flock the interior of the scope.

I flocked the interior of my RCOS and it seemed to improve it, it increased the contrast in images. I also made an aperture mask for the mirror in case of turned down edge which per the RCOS site makes for bloated stars. So perhaps you may have a little of that too. I simply got some black cardboard from a newsagent and did a cut out and taped it to the side of the mirror with little tabs turned down so the last 5-10mm of the mirror was masked.

Greg

[peter_4059]

Beautiful set of images Paul. Can you let us in on the capture details?

[dpastern]

See post #31 here:

http://www.iceinspace.com.au/forum/showthread.php?t=44533&page=2

Some of AlexN's shots have shown the reflections as well.

Dave

[marki]

They are turning out to be quite good indeed aren't they (dam no emoticon for standing on a chair whilst cheering for the underdog :)).

Great pics Paul, I am loving your blob free results and have put enough away to buy the 10" when it finally turns up.

Mark

[Alchemy]

REALLY NICE IMAGE

beautiful detail, tight in the dust lanes. youre going to have a great time with that scope. Bargain at under 3k


clive

[dugnsuz]

Very nice images Paul - I'm sure there will be lots of people out there in the Astro-Community worldwide very keen to see some decent results from this scope - you've provided them!
Exciting Times!!
Doug

[Matty P]

Amazing images Paul. Definitely shows the quality of this little RC.

I had my reservations about this scope but after seeing these images, it has really changed my mind.

Now it's time to start saving for one! :doh:

Hope the internal reflections can be sorted out quickly. :thumbsup:

[AlexN]

I think the internal baffles could be causing the reflections.. I dunno... Maybe a can of flat black paint could make all the difference.. However due to the primary being fixed, I don't know if I like the idea of pulling the scope apart... I do wonder if theres a way to test that out...

[Octane]

Paul,

Fantastic images. I agree with everything so far said about the Chinese manufacturers (cheap RC). I thought my mind may have been swayed by that dude that posted in the other RC thread, but, after having seen the potential here, have changed my mind.

I know what my next telescope purchase will be.

Regards,
Humayun

[Virgs]

These results speak, no they SHOUT for themselves and being there whilst the second night of testing was being carried out allowed me to see what these scopes are capable of. These little babys rock! They are a delight to use and given that Paul was using a modified Canon 40D DSLR puts it into perspective - you can now match the big boys without having to spend a huge amount of money. For those of you are thinking about entering the next level of imaging, these should be a consideration. one wonders what the results may be when we chuck an ST1100 on the back - hint hint Mark..

[Max]

Hey Paul!!

Great Images!!!!! and Great scope!!!

Regards!!!

Max

[peeb61]

Very nice indeed Paul...love all three and I'm turning green!

Paul

[wysiwyg]

Very nice images Paul,

It looks like this scope is going to be the next bang for your buck type of scope. RCOS are already reducing their scopes by 20%, thats nearly $10K off the price of the 16".
Maybe they saw your photos :lol:

[desler]

I know it;s all a learning curve, but boy, these images are just so nice, it makes me feel pretty low down the food chain.

I'm so happy that your finally getting the results you hoped for Paul, well done!


Darren

[Peter Ward]

Yes, it's amazing what you can do with a $A12,000 Taka mount and $3K OTA these days :)

[TrevorW]

Pete is that a touch of sarcasm I hear or are my eyes deceiving me

;)

[Peter Ward]

:lol: Nah...(and taking nothing away from Paul's images) just stating the 'bleedin obvious...

[AlexN]

bleeding obvious being that the mount is the most important part of medium to long focal length astrophotography? (or great images in general?) :D Not to mention knowing your gear and how to get the most out of it?

:)

[dpastern]

hahaha! Seriously, the 12" variant of the GSO RC is within reach for a lot of people (from memory, it'll be priced around US $4700) - if it performs like the 8" is doing, but with more light gathering ability, it'll hold serious potential. As long as optical quality stays good (and mechanical quality now that I thinik about it), they're going to start killing RCOS sales. And that's great - RCOS gear is way over priced. Those guys probably have a 500% markup.

Dave

[TrevorW]

Dave they haven't made a 12" yet you are quoting the 10" prices

[Hagar]

Looks pretty good Paul, You have to be happy with results like this. The scope looks like with a little effort it will be one of the new class of scopes set to change the overall costing of astronomy equipment for the future.

The apparent reflection you have on the bright stars is evident on my VC200L as well but was improved with collimation but may be something you just have to put up with. Looks like I had better buy a copy of CCD inspector. It worked OK during the trial period. So might be a required bit of kit with the RC or the Vixen to keep them in check.

[dpastern]

Not according to Astronomics. They've been advertising it heavily for the past 2 months in various magazines. US Pricing be noted.

6" - 795
8" - 1995
10" - 2795
12" - 4495

Page 23 of May's Astronomy

:-)

Oh, and there's talk of a 16" for around 9 grand US or so.

Dave

[marki]

Dave is correct, its all there in black and white with a comment about being able to buy a compact car with the change you save buying the astrotech 12" instead of buying a RCOS. Interesting in that the 10" and above includes cooling fans in the price. Do you think they might be getting serious about this?:)

Mark

[Peter Ward]

All of the above. A poor mount will ham-string even the best optics on the planet.

[leinad]

http://www.astronomics.com/main/documents/print%20ads/astronomy%20may%2009.pdf

[Peter Ward]

Of course, all the hyperbole must be true....the same ad also reads:

"And Meade’s 6” f/10 Advanced Coma-
Free (ACF) catadioptric optics deliver the
same sharp coma-free view as a professional
Ritchey-Chrétien telescope, but
without an R-C’s high price tag"

;)

[TrevorW]

Dave that must be old advertising as Astronomics home page makes no reference to the 10" or bigger and they are selling the 8" for around $1400 USD currently , I've seen the 10" advertised on a Sth African site for around $4700 USD, I suggest we don't speculate to much on content and price in OZ until someone here ie: Andrews actually advertise it

http://www.astronomics.com/main/category.asp/catalog_name/Astronomics/category_name/U5QNWB3RKWWL8N3EL99F9DX9A0/Page/1

[kinetic]

that's hyperbole Peter :)

[Peter Ward]

:lol: Freudian slip...I was thinking of the shape of the optics

[dpastern]

Trevor - check CN - there's *lots* of reports from NEAF about 10", 12" and 16" all coming in the near future. Astronomics, not GSO. GSO is an OEM, as well as their own named brand. Andrews is buying the GSO RC's. Astromonics has commissioned GSO to make 10", 12" & 16" RCs along the same lines as the 6" & 8" that they natively manufacturer as OEM/branded name. Yes, the hardware is made by the same company, but that doesn't mean that GSO will provide 10" and above RCs. I presume they will, it makes sense to, at least R&D wise and economics wise.

Dave

[dpastern]

I doubt that many people are going to honestly be able to tell the difference between an image taken with a 12" GSO RC and a 12.5" RCOS RC. At least, when both units are properly collimated, decent mounts are used, good tracking, good exposures and the same CCD imaging gear.

I've seen the same disdain in the photography field, where those using pro cameras treat those using non pro cameras with utter disdain and contempt.

This can only be good for the industry - like the Dinosaurs, these overly priced brands will *have* to adjust or die. The days of massive markups are over I suspect, and as a consumer, I'm quite happy with that. I don't particularly care if RCOS cries poor, or stops making such a large profit, that's not my problem. Maybe if they didn't sell their products with such massive markups, they'll retain some market share. I guess it'll depend on how greedy they are. They'll certainly play on their "name", much like Nike & Reebok play on their names in the shoe industry. A name is name, it's no guarantee of quality, or a reasonable price for that matter.

I can understand some RCOS owners becoming upset if a 12" GSO RC performs with 95% of a RCOS RC at 15-20% of the price, they'll find it hard to justify their expenditure I suspect ;-) And they'll be mightily jealous of those that are getting near performance at a fraction of the price.

I do suspect that the RCOS RC's are definitely better optically, and mechanically, and probably feature wise, but the question is, by *how* much, and is the huge price difference justified? I suspect not!

As to Meade, despite my dislike for the company and it's average products (imho), the LX200 ACF units have a reasonable reputation for optical quality, leading to reasonable imaging with the units. Sure, Meade did a major stuff up when it announced the ACFs as being Ritchey Chretiens, and it didn't win them any friends in the industry I suspect.

Dave

[AlexN]

good post dave. All these comments carry an overwhelming element of truth, but the fact is that consumers are generally the same in every field. There will always be bargain hunters wearing clothes bought from target, and there will always be people paying 80% more for nike, despite the quality of the products being similar. Name brands will always carry weight in the market. People will still buy rcos scopes even though they can get similar quality images from a gso at a fraction of the cost.. I know if i had the money i would own am rcos on an astrophysics 3600 gto mount regardless of if i could get similar images from a gso rc and a celestron cge pro mount. Why? Because they are the best. If you can afford the best, you buy the best. If not, you make do with what you can afford. Luckily for ur, gso have just made what we can afford a whole lot better.

[Peter Ward]

That may well prove to be prophetic....but I'm still inclined to adopt a wait and see approach.

However I don't think the value of albeit less expensive, but good RC telescope, will affect RCOS anymore than a luxury Hyuandai would affect S-Class Benz sales.

A 12.5" optical set (from Star Instruments, the RCOS supplier) alone will set you back a cool $US6000..... Why? For starters the optics are Zygo tested and certified to 1/25th wave RMS, and have thermal properties an order of magnitude better (actually 20x better) than the fuzed quartz by GSO. (BTW this talk of 500% mark-ups is utter nonsense)

I applaud Paul's ingenuity. By adding a more robust and accurate focuser and adapting 3rd party field flattner to a modest scope, plus putting the ensemble on a top-of-the-line mount, he is indeed getting a great result!

But we are hardly talking about "cheap" systems out of the made in China box anymore.

[marki]

Come on Peter, you know it's true, surely you wouldn't question meades excellent and highly aggressive marketing campaign :P:D :rofl::rofl::rofl:

Mark

[Paul Haese]

Thanks guys,

for this is all about having a go with an affordable solution. The mount, focusor, and flattener all enhance what looks like a good little scope. Certainly not an RCOS. I have checked other guys images, but I am happy to report that the images stack up well generally. That means there is room for improvement on the capture side and certainly from the processing side.

I like the fact that a person can buy a good OTA for 3k (including the focusor) and get nice sharp images. That is what is important. If you want to own a Roller buy the RCOS. If you cannot afford that, well this is a good option.

Once again thanks for the comments and thoughts.

[kinetic]

I totally agree on the comments on mounts by Peter,

Here's a great post by MonteWilson that sums it up best:
http://www.iceinspace.com.au/forum/showpost.php?p=214469&postcount=13

Steve

[dpastern]

Peter,

I think it will affect RCOS, more so than Benz, simply because there is very little competition in RCs. In this day and age, people are looking at their dollars twice, three times, nay, 4 times or more. If I had the money, I'd probably buy an RCOS, because they are the best, there's no argument there. But - the GSO RC comes close, for a fraction of the price. Again, all this talk about 1/12 wave, 1/25 wave, etc etc - I honestly doubt that the average person could tell the difference between those 2 measurements in real life images. Again, like with another hobby of mine (hi fi), all these fancy measurements are great, but they generally mean bugger all in the real world, and that's *what* counts. I've been around far too long to believe that measurements holistically accurately describe the real world characteristics of something.

I don't begrudge you owning a RCOS (sorry if I sound that way, it's not my intention) - I simply dislike artificial pricing for the sake of making a buck because people are gullible enough to buy the item, instead of walking away from it when they realise that the item is way overpriced. I've spoken to a few people in private, and one person in particular used to work for RCOS and he guaranteed me that they have huge markups.

Dave

[dpastern]

Oh, I agree, I consider mounts the most important part of the equation. But, even the best mount will not be great if you don't accurately polar align, etc. I've seen people with Paramount ME mounts, whose images have been well, not very good. And they had expensive OTAs too. Just because you have an expensive item, doesn't automatically guarantee that you'll know how to eek the best out of it. Hell, I'm struggling to get 15 second images out of my very modest setup without trailing (and I'm currently losing the battle I might add). I'm sure that once I get my act together, I'll start being able to get better images.

Dave

[TrevorW]

And on the other hand I'm aware of several amateurs who have captured exceptional images with only modest equipment so taking the car scenario just because you may own a Porsche it doesn't make you a race driver.

Also like Peter said these scopes are not designed to compete with the likes of RCOS which are just in another ballpark.

It's like anything in life if you can afford the best then buy it otherwise make the best of what you can afford.

Pauls images show the potential of this scope and thats all.

[RB]

Steve I agree, the mount is *the* most important piece of equipment as far as I'm concerned.
Followed closely by the person's processing skills once they've gathered the data.

Around the forums I've seen lots of people spend a lot on scopes and camera gear, only to be let down by their processing skills.

At the end of the day it basically boils down to what you do with your data.

As for the GSO's, it's nice to see they have the potential to perform. :thumbsup:

[Peter Ward]

Sorry Dave, looks to me like you have a "tall poppy" attitude to RCOS.

Close?

......so, GSO has ion milled zero expansion optics with .96 strehl or better? an absolute position focuser re-produceable to 1/50,000th of an inch *and* tracks focus with temperature changes? Ultra rigid carbon fibre truss that delivers ~20 arc sec all sky pointing? Primary, Secondary and ambient temperature probes and thermal control? Adjustable primary, secondary and baffle? High torque 1/100th of a degree instrument rotator option? dedicated 70~120mm wide field flattner? External Stepper remote control...plus all of the above controlable via a local PC, network or internet?

Of course it doesn't, and all of the above costs $$$

But it's a great little scope...and represents an excellent solution for many....but I'd suggest it's still not a Benz :)

[AlexN]

Well said Peter.
The RCOS are expensive, however they represent a whole new level of control and monitoring over the telescope system. The cost of all the electronic extras is half the reason they are so damned expensive, although to some users who are setting up remote observatories, these are requirements. The RCOS scopes fully optioned are an unparalleled imaging platform..

The GSO is a very nice compromise for those of us who dont require ion milled optics, temperature controlled focus or telescope command center.. (I wouldnt mind a RCOS instrument rotator though!! :))

[jase]

Lovely images Paul. Kudos to you for the effort you're putting in. Saw those reflections in the other post - interesting. I'd probably be focusing on the secondary light shroud/housing. Perhaps create an aperture mask and tape it on to see if that alters the situation. Keep at it.

Wha!! Why are people comparing an RCOS RC with a GSO RC? Different league all together. Sure they share the same optical design, but that's where the similarities end. A more comparable RC to the GSO would be those produced by Deep Sky Instruments - http://www.deepskyinstruments.com/products.htm. Personaly, I'm keeping an eye on their 14" expected to be released soon. Sure, these are more expensive than the GSO's, but you pay for what you get. The name "Ritchey-Chrétien" does not insist optical perfection - RC's are not all created equal!

If you're going to make comparisons with an RCOS RC, you'd want to be comparing it against something like the A&M RC's - http://www.astrotechengineering.com/Default.aspx?ID=156.

[bluescope]

Nice images Paul ... especially 5128 ... everyone seems to have bogged down in a debate about gear again when what really counts is the images and your enjoying your hobby ;)

:thumbsup:

p.s. The only comment I would make about the 5128 image is why is the brightest blue star below the galaxy seemingly slightly out of focus i.e. the spikes aren't aligned ... all the others are fine :shrug:

[dpastern]

Peter - let's take a step back and look at things.

1) Paul has been able to get some fab images without all those "extras".

2) said images look good to me.

ergo one can deduce that:

3) said extras aren't entirely necessary - one can grab quite nice images without them. Sure, if they float your boat, go for it. For me, and I suspect, many others, they don't.

Do I need the kitchen sink with a scope? No. Do I want it? Not really. Can I afford it? No. Can I justify X amount for a RCOS? No. Not when alternatives can do what it does, for a fraction of the cost. People insist on being silly and apportioning quality to a brand name, and it's dangerous. Brand name does not equal quality, well not always - there's no guarantee. As a society, we're so heavily taken by "image", that other things tend to be ignored. I ain't one of the Joneses (if you haven't noticed by now lol).

Dave

[AlexN]

Agreed Steve, Good call... Who cares about the brand name or optical design. If the gear is producing images that you're pleased with, then its good gear... Doesn't matter if it cost $30,000 or $3000.


Dave - In the case of companies like RCOS, Planewave, Astro Physics etc, The Name brand only got the reputation that they did by making exceptionally high quality products with very low tollerance for error. The quality actually is gauranteed from names like the afforementioned...

[Peter Ward]

Agreed. :thumbsup:

The merits of various scopes (which I'm always happy to discuss) should be taken up elsewhere.

[pgc hunter]

fantastic! Loving the Trifid and Eta Carina shots!

[dpastern]

Yes, perhaps it's better to do that :-) I didn't meant to offend you Peter (hopefully I haven't). I just simply have one particular point of view that differs to yours.

Dave

[AlexN]

Dave, I wouldnt worry. To my understanding you can't actually offend Peter. :)

[EzyStyles]

Fantastic images Paul! Definitely up there with the rest. I have seen you come a very long way. Your effort, dedication and commitment have produced these images :)

Hi Steve, the twin spikes in 5128, theres 2 bright stars next to each other. nothing got to do with focusing :thumbsup:.

In terms of equipment, do the best of what you can afford :thumbsup: the GSO RC might be one on my list soon.... .thanks Paul :)

[strongmanmike]

Three very excellent images Paul :thumbsup: after some initial frustrations I bet you are pretty happy sitting at your computer looking at these :)

:clap:

Mike

[bluescope]

Thanks for pointing that out Eric ... it did baffle me as to why ... I didn't realize there were two close stars there.

:thumbsup:

[Paul Haese]

Yeah only minor frustrations though Mike really in the scheme of things. I reckon I could go deeper on the 5128 though. What do you think? ;)I was thinking of doing a deep field centaurus A. I reckon I read where someone else did the same thing.:P

In all seriousness though, very happy thus far with the results. More work to do though to get that perfect image, but this is a very good start. Looking at monochrome cameras now again. More research and more thinking. I am thinking of front illuminated but not sure which company to go with. I can only use and APS size chip though as full frame will be vignetted too much I think. At the moment it is a toss up between the QSI583 or the STL6303e. I cannot afford an FLI or an Apogee, not keen on separate filter wheels either. Also like the idea of using a camera with self guiding too, but affordability is the main issue.

[Craig_L]

Hi Paul,

Great images - scope and camera working very well as everyone has commented. What length extender tube did you use to get focus with the Canon? And I wonder whether this would be the same for the 6 inch which I'm thinking about?

[Paul Haese]

Craig, I used the 2" extension behind the focusor and in front of the focusor I used Takahashi CA35. This has given me the correct length for focus. The long CA35 is used so that I can use the Taka flattener.

[Craig_L]

Thanks for that Paul. I have a Tak flattener but for my Sky 90 but I mightn't need it for the 6inch which I understand is pretty flat to the edges. My only worry now is whether I have to use dew heaters.

[AlexN]

Craig, I think I'll be making a dew heater for the secondary.. As on a dewy night, the secondary fogs up pretty quick.. The primary seems well protected. But I'll make a dew shield first to see if that keeps it at bay, if not, secondary heating setup will be built..

[TrevorW]

Dew whats dew

[Craig_L]

Must be that mild Western Australian weather Trevor. Thanks Alex. Hmm. Dew heaters, collimation, internal reflections...my feet are getting cold.

[TrevorW]

Hi Craig

Don't generally need dew heaters here until Sept/Oct when it gets below zero at night

All these issues you mentioned are indicitive of RC, Schmidt Cassegrains and Newts, dew can hit anyone so don't be put off by that and collimation as all reflector type scopes need this done regularly.

Th reflection artifact may be something simple to fix and we are working on that.

Cheers

[AlexN]

hah.. If all it takes to cool your feet is collimation, dew and a reflection that may be easy enough to fix, you best stay away from telescopes...

Newtonians - Require collimation, require secondary dew heaters
Refractors - require heaters, can get reflections
SCT/Mak Newt/MCT/SN - can get reflections, require collimation and dew control.

No matter what scope you buy in this price bracket, there are going to be extras to buy, there are going to be modifications to be made and issues to rectify... If a bit of dew control, careful collimation, a focuser and an internal reflection is all this scope needs to be as good as it can be, I say its awesome.

Alex.

[leinad]

That internal reflection would drive me insane!!; I don't know about you guys?

Hope the supplier provides some fast answers. Does the Astrotech model have the same problem; possibly email Astrotech directly ?

Could this be possibly off-axis aberration? I'm suprised you've all been hit by this same problem. Sounds like a defect to me.

Hope you sort it out soon :thumbsup:

[AlexN]

I emailed astrotech 3 days ago with regards to their announced 0.75x reducer/flattener, and also asked about the internal reflection... I am yet to get a reply.. Waiting, waiting waiting...

I highly doubt its an aberration, more likely light shining off something inside the OTA.. My current thoughts are secondary baffle, the end of the primary baffle tube and possibly the mirror edge... An aperture mask made for the two mirrors will either identify that as the problem, or rule them out.. then I'd be looking at the other options... At the end of the day I would imagine that this wont be something thats extremely hard to fix.

[leinad]

Out of curiosity; how does the reflection look when the camera is slightly out of focus?

[AlexN]

softer.

[TrevorW]

As I stated on the other thread I got no reflection in 6 minute subs of Cent A

I'm betting on the primary baffle being the issue

Cheers

[leinad]

Just saw something similar here:
http://www.narrowbandimaging.com/mark_i_classical_cassegrain_hex.htm

Perhaps it is the tubes focuser baffle tube..

[dpastern]

What's the primary baffle?

Dave

[TrevorW]

Dave

It baffles me too

see the short and long black thingies in the middle of the scope in the images from the link posted by Leinad they are the baffles

Cheers

[leinad]

Meant to say the focuser baffle tube. :P

[AlexN]

Daniel, That link you posted does show a VERY similar reflection, and apparently flocking the baffle tube fixed it (as seen in the image)

[TrevorW]

OK Alex are you game (refer post on SCP)

Cheers

[AlexN]

Dude... Not yet hey... but it does look like it will fix the problem..

Out of everyone I know who owns one of these scopes, Paul has the most experience with dismantling scopes...

[dpastern]

Ah, the black support rods that tie the front and aft sections together?

Dave

[TrevorW]

Funny man DAve, Alex the primary baffle tubes internal diameter is about 37mm and about 127mm long I was thinking about a set of baffle rings to fit inside this say each baffle 2-3 mm width

:lol:

[AlexN]

Dave,

The baffle is a long tube that extends from the centre of the primary mirror upwards towards the secondary mirror. Its whole purpose is to stop extraneous light reflections and to increase contrast... baffles like this are used in most compound scopes (SCT/RC/MCT) however if they are made of a reflective material, sometimes they dont serve their purpose...

[leinad]

It does doesn't it. I hope this helps. I'd be a little worried though that the manufacturer didn't address this issue.
Hopefully the manufacturer provides a positive response to a fix; I'd hate to resort to pulling the thing apart. :sadeyes:

[dpastern]

Ah, I get ya. lol!!!

Dave

[Paul Haese]

Couple of things here guys.

I have used my scope several times in very dewy conditions, never had the scope dew up yet.

Now in terms of the reflections, how bout not A) discussing it here (use the other thread) and B) lets not just assume this is a manufacturing fault. That is not productive, the scopes work fine, let us find out what the problem is and not speculate. If it were a common problem it would show up in every image.