Advice on new telescope/accessories

[raymo]

DSLRs used with skill and commitment, can get very close to the image quality of CCDs. I look at the best images from both, and wonder whether
the small difference is worth the extra cost,[ unless you are one of the world's finest imagers, and demand the absolute best]. If you really like
your 5D, I suggest you stick with it, for now at least.
raymo

[kkara4 (Krishan)]

thanks Dunk and Raymo for the replies - I will stick to the 5D for now then and see what I end up with!

[kkara4 (Krishan)]

Originally Posted by Camelopardalis

Depending on your climate, a SCT may or may not be suitable. Down here in Sydney, I find that the corrector starts dewing around 85% humidity. So long as it stays around that it can be somewhat controlled with heaters, but at that point you're introducing additional local thermals that could affect your image quality.

I also have the Tempest fans fitted to my C11 Edge HD and they're great for equalising temperature gradients but have also found I need to watch the dew situation as they push so much air - and potentially moisture - thorough the tube, I've had it dew up on the inside a couple of times I've just learned to use them sparingly. They are great though and don't introduce any discernible vibration into the image.

Take a look at the RC scopes such as http://www.bintel.com.au/Telescopes/...oductview.aspx they cost less at least in the smaller sizes than SCTs and have no corrector to dew up. I'm very happy with my Edge HD scope, but I'm mostly into visual...

Also, I'm no DSLR expert, but for planetary you might be better off with one of the faster frame rate CCD cameras, but a 5D should be nice for DSO imaging and at f/8 the RC-8 should give you a wide choice of the fainter targets to work on

Just a suggestion, but an RC-8 on AZ-EQ6 might be an interesting place to start, but the mount is everything as the focal length increases...

Dunk, would this be the dew shield required if I did have a dewing problem?

http://starizona.com/acb/Astrozap-Al...P3167C121.aspx

I think I would be naive to believe that I wont have a dewing problem, id rather consider it and be prepared for it than not. At the same time I dont want to make things too complicated!

I had a look at those GSO RCs, and then looked up some info on advantages and disadvantages of RC vs SCT for astrophotography. After reading this thread http://www.cloudynights.com/ubbthrea...fpart/all/vc/1, I think I want to stick with SCT, I dont like the sound of collimating an RC constantly! It also sounds perhaps like the Edge HDs have maybe a slight advantage over the RCs, although I must admit I dont understand some parts of the discussion in that thread! (yet)

[The_Cat (Jeremy)]

re: Undoubtedly, some will suggest an Astrophysics or TAK mount. I dont know much about either. Astrophysics makes good gear. "

In this day and age Electronics is very cheap but precision mechanics is always very expensive.

If you are looking at these mounts then the Takahashi mounts are better value for us in Australia. EM200 class is very good at c. $7000. The AP mounts are exceptional the smaller one is the mach1GTO BUT if you order one remember that every thing is an option so the price will be (in $us) very high and Customs will love you for importing one.

... Go on get one and help reduce the country's deficit !!

Clear skies,

Jeremy.

[kkara4 (Krishan)]

Originally Posted by The_Cat

re: Undoubtedly, some will suggest an Astrophysics or TAK mount. I dont know much about either. Astrophysics makes good gear. "

In this day and age Electronics is very cheap but precision mechanics is always very expensive.

If you are looking at these mounts then the Takahashi mounts are better value for us in Australia. EM200 class is very good at c. $7000. The AP mounts are exceptional the smaller one is the mach1GTO BUT if you order one remember that every thing is an option so the price will be (in $us) very high and Customs will love you for importing one.

... Go on get one and help reduce the country's deficit !!

Clear skies,

Jeremy.

Thanks Jeremy but I think I won't contribute to the defecit for the time being .

I will take a look at the mach1GTO though, but sounds way too expensive at this stage!

[Camelopardalis (Dunk)]

Originally Posted by kkara4

Dunk, would this be the dew shield required if I did have a dewing problem?

http://starizona.com/acb/Astrozap-Al...P3167C121.aspx

I think I would be naive to believe that I wont have a dewing problem, id rather consider it and be prepared for it than not. At the same time I dont want to make things too complicated!

I had a look at those GSO RCs, and then looked up some info on advantages and disadvantages of RC vs SCT for astrophotography. After reading this thread http://www.cloudynights.com/ubbthrea...fpart/all/vc/1, I think I want to stick with SCT, I dont like the sound of collimating an RC constantly! It also sounds perhaps like the Edge HDs have maybe a slight advantage over the RCs, although I must admit I dont understand some parts of the discussion in that thread! (yet)

I use the Astrozap flexible dew shield (for 11") as I find it squishes into a space in the car better I also have the heated version, although at some point I will get my hands on a separate heater tape as there is some evidence that heating the aluminium tube just behind the corrector is more effective at keeping it dew free than heating the thicker black (steel?) ring around the corrector. If you're serious about dew, check out the DewBuster

I've heard the RC can be a bit more interesting to collimate, but it also lacks a corrector. It's a difficult choice

As everyone has said, choose your mount carefully.

[kkara4 (Krishan)]

Originally Posted by Camelopardalis

I use the Astrozap flexible dew shield (for 11") as I find it squishes into a space in the car better I also have the heated version, although at some point I will get my hands on a separate heater tape as there is some evidence that heating the aluminium tube just behind the corrector is more effective at keeping it dew free than heating the thicker black (steel?) ring around the corrector. If you're serious about dew, check out the DewBuster

I've heard the RC can be a bit more interesting to collimate, but it also lacks a corrector. It's a difficult choice

As everyone has said, choose your mount carefully.

Thanks Dunk, so it looks like there are heated and unheated dew shields then? Hopefully some other Brisbanites can provide some recommendations! Otherwise a heater sounds like an idea. Wont a heater though give you tube currents?

[Camelopardalis (Dunk)]

They're the same thing, pretty much - the heated shields just have the heater band in the (scope) end of the shield, that wraps around the thick metal around the corrector. The heater tape is more versatile IMO, in that you can vary the position more easily and find what is most effective for your scope/where you are.

Certainly, there's the risk of tube currents. It comes down to a bit of experimentation...if the heater is up too high, you can pretty easily see the heat haze, at least through an eyepiece.

[kkara4 (Krishan)]

Originally Posted by Camelopardalis

They're the same thing, pretty much - the heated shields just have the heater band in the (scope) end of the shield, that wraps around the thick metal around the corrector. The heater tape is more versatile IMO, in that you can vary the position more easily and find what is most effective for your scope/where you are.

Certainly, there's the risk of tube currents. It comes down to a bit of experimentation...if the heater is up too high, you can pretty easily see the heat haze, at least through an eyepiece.

Thanks Dunk, I agree the tape version sounds better, I suppose there is a learning curve with all of these things and experimenting is the key!

[Camelopardalis (Dunk)]

Yeah, all part of the fun

[kkara4 (Krishan)]

Originally Posted by Camelopardalis

Yeah, all part of the fun

And as for the mount, looks like im about to pull the trigger on a G11 G2. I think it will be excellent for a C9.25 sized instrument (from all the replies so far and reading Ive done elsewhere) and all the accessories, and the weight will be manageable to boot. I like all the features and options for adding things in the future as well.

[Camelopardalis (Dunk)]

Very nice mate

Btw, just my opinion, but the Edge HD scopes are a nice visual scope - try it with an eyepiece sometime

[kkara4 (Krishan)]

Originally Posted by Camelopardalis

Very nice mate

Btw, just my opinion, but the Edge HD scopes are a nice visual scope - try it with an eyepiece sometime

Thankfully it comes with one! As to how decent the included one is I havent looked into but I certainly plan to stick it in every now and then .

[Camelopardalis (Dunk)]

ah it'll be OK for a look now and then

[kkara4 (Krishan)]

haha. OK so here is the shopping list:

Celestron 925 Edge HD OTA
Losmandy G11 G2 with tripod (trigger pulled)
Starizona cooler
Starizona feather touch microfocuser

And things im unsure of:

Televue PowerMate 2" 4x
Televue PTR-4201 T-Ring Adapter
Canon T-Ring adapter (from somewhere?)
Celestron dovetail adapter to mount to the G11 (needed?)
Dew Shield/heater TBD
12V power for mount?

Anything im missing?

Also has anyone bought from:
http://www.andrewscom.com.au/site-co...-celestron.htm, and have any regrets?

[Camelopardalis (Dunk)]

What's the Starizona cooler you're looking at? If it's a gizmo that goes up the baffle tube you won't be able to use it since the Edge HD models have the corrector lenses lurking up there. For cooling your primary mirror area, I'd recommend the TEMP-est system.

Feathertouch micro focuser...not essential IMO...but check on the scope first whether it's got the large rubber focus knob (like the C11) or the smaller one (like the C8) as it's pretty straightforward to find focus with the bigger knob.

You'd probably benefit from a bahtinov mask or similar focusing aid - you can either make one yourself or buy one suitable for the scope.

Canon T-ring adapter shouldn't be hard to find, for example, BinTel one

You'll also need to interface the camera with the rear cell of the scope. The Edge HD 9.25" uses a 3.25" rear thread like the C11, so if it was just the camera, you could use something like the Celestron adapter, but I'm not sure how you'd interface the Powermate with it...the Celestron adapter has a male T-thread.

[Camelopardalis (Dunk)]

Btw, this is rolling of the tongue relatively easily because I recently decided to start doing some photography with my own Edge scope (with the guidance and teaching of best bunch of guys you could hope for ), so I'd not long back done all this reading around myself

[kkara4 (Krishan)]

Thanks Dunk! Always helps when someone is looking to go down a similar route!

The cooler I was looking at was
http://starizona.com/acb/Cool-Edge--...5-P3497C0.aspx

Although that may not be necessary if the Temp-est system is used?

I am just assuming that the powermate goes where the eyepiece would normally, but actually have no idea if that is correct or not, so thanks for your rear thread comment! I will have to look into this further.

[The_Cat (Jeremy)]

Regarding:

"Canon T-ring adapter shouldn't be hard to find, for example, BinTel one "

Please note that if you intend to use a full frame size CCD be it EOS or any other you must consider a "Wide T" mount. Using a standard bayonet fitting on a standard T2 thread will show edge darkening , aka vignetting, of the image on these large CCD's.

Jeremy

[Camelopardalis (Dunk)]

Yeah it's still fresh in my mind, still experimenting but been getting some interesting results! Very exciting times

The Cool Edge basically goes in the hole opened up when you remove the Fastar secondary mirror. This is fine if you want to cool it down quickly at the start of a session, but you have to remove it and put the secondary mirror back in place before you can do any imaging The Tempest system also do a secondary fan, same problem obviously. The more interesting ones are the Tempest fans that replace the side vents on the Edge HD tubes, as these are permanently mounted (it's only 2 little screws) and can be on while you're imaging, drawing a constant stream of air past the back of your mirror. As I've found out, just be careful if the air is moist and the temperature dropping as it'll draw moist air in there too and I've had my corrector mist up on the inside maybe I should have just had the dew heater up higher

I'll be interested on what you find for the powermate... at the moment, I use a Clicklock visual back with Televue 2" to 1.25" adapter before the 2.5x powermate... but my little camera is only the size of a 1.25" plossl