Seeking advice on 10" scopes (or is that ED80s?) - Page 2

DaveO (David) · #21 10-03-2006, 03:57 PM

OMG! Well if I wasn't convinced before, I am now. Thanks for the feedback. I am finding this most useful.

To answer a previous question, my main interest is DSOs. While I know the greater aperture of newts is useful in this regard, my prior assumption that large aperture was a prereq is now shattered.

I have also spent the morning at one of the local astro shops (Sirius Optics). At the risk of taking the thread completely off-topic, I am now going to look at 80-100 EDs in a little more detail. One thing I like about them is the portability and the reduced storage space (something the "Minister for the Interior" is also interested in!).

Sirius have an 80ED with EQ5 GOTO mount for $3240. Only one of the 2 lenses in the doublet are actually ED glass, but allegedly it is pretty good. Anybody able to comment on this or equivalent gear?

ausastronomer (John Bambury) · #22 10-03-2006, 05:50 PM

Quote:

Originally Posted by DaveO

Sirius have an 80ED with EQ5 GOTO mount for $3240.

Dave,

Thats a really good little scope. Shop around, you can buy this OTA only for about $500 to $600 and a suitable GOTO EQ mount is about $1600 so they are $1,000 off the pace.

CS-John B

[1ponders] (Paul) · #23 10-03-2006, 06:18 PM

You're getting some great advice here DaveO.

I have both Orion 80ED and an 8" meades sct (and am thinking of getting an 8 or 10" newt for imaging). Atm most of my imaging is done with the 80. Many of the DSOs you will probably start out trying to image will be close on size to a full moon or bigger, (moon - 30 arcmin, M42/43 - approx 1.5 deg, Keyhole (Eta Carina) - over 2 deg, Tarantula - 40 arcminutes, Silver Coin Galaxy (ngc253) - 25 arcmin). Do an advanced search in the Deep Sky section for the 80ED and check out some of the imaging being done with it. Hopefully if you aren't already convinced you will be.

You will eventually want a longer FL scope to start on the smaller DSOs but there is a hell of a lot out there to break your teeth on and lessen the slope of the learning curve. The longer the focal length the bigger the challenge. About the only time I use my 8" now is for moon shots and planetary imaging if the night is worth it (few and far between atm). And there is another thing. If you get a mount that has lowish periodic error and you polar align really well you may be able to do unguided shots for a minute or so with the 80. That will be much more difficult with an 8 or 10 inch scope. And btw, don't forget you might want a guide scope at some time so the 80 doubles up for that as well. Wack in a 4Xbarlow for visual guiding or as it is for autoguiding.

IMHO to get you up and running? EQ6, 80ED (guiderings and any old 60mm tasko for a guidescope) camera and reticle (for guiding) and away you go. (Sort of

)

Once you've got that and played with it a bit you will definately have a better idea of where you want to head next.

[1ponders] (Paul) · #24 10-03-2006, 06:24 PM

DaveO have a look here http://www.iceinspace.com.au/forum/s...ead.php?t=8103

Yes it is more expensive than the 80 on it's own, but this is an exceptional setup with the focuer and guiderings.

DaveO (David) · #25 10-03-2006, 07:27 PM

Quote:

Originally Posted by [1ponders]

DaveO have a look here http://www.iceinspace.com.au/forum/s...ead.php?t=8103

Yes it is more expensive than the 80 on it's own, but this is an exceptional setup with the focuer and guiderings.

Paul, yes I agree, the advice her has been as good as I could have hoped for. And truly appreciated.

I had already looked at that scope you identified, but with my limited experience, I was not sure exactly what I was looking at! For example:

Is this the same as what I would be buying now?
What is a "traveller focus"? I understand the difference between R&P and Crawford, but this is new.
Why are Losmandy rings so special?
I have no idea what a reducer is or a compression ring!

Any enlightenment would be appreciated.

[1ponders] (Paul) · #26 10-03-2006, 08:12 PM

Hi DaveO. The optics of the scope are the same, though the focuser is a dream (I did a bit of research on it when I was thinking I might need to upgrade my 80 focuser for upgrade. I didn't need to but I still thought long and hard about it. See here

I have two sets of losmandy rings and if I needed another set of rings I wouldn't think twice about getting another set, even at that price. They are weighty though and you need a losmandy dovetail to mount them but I wouldn't be without mine. Check them out here I've not compared them to other topend guiderings.

The compression is a brass ring inside the eyepiece sleeve that takes the place of the one or two thumbscrews that tighten on eyepieces to hold them in. Pretty much a standard for higher quality focusers etc. Tensions evenly around the circumference of inserted fittings rather than having the thumbscrews push it up against the other side of the sleeve. Much more secure, and you can rotate the eyepiece etc without loosening the compression ring (as long as its not too tight).

The focal reducer field flattener speeds up your scope (less exposure time) widens the field of view (can be a + or a - depending on what you want to image) and flattens out the field curvature of the imaging lense. Often highly desireable for medium to slow f/ratio scopes, particularly SCTs and Refractors. From what I understand Newts use coma correctors which are similar (flatten the field) but don't change the f/ratio (Don't know newts so I'm only assuming here. Is this correct anyone?)

AstroJunk (Jonathan) · #27 10-03-2006, 08:15 PM

Don't spend a cent till you've been out with us on a DSO or LPO night Dave - I see you're a fellow member of the AAQ. We have a very representative sample of scopes which are regulars in the field.

Play first - Pay later, that has to be the best advice ever!

[1ponders] (Paul) · #28 10-03-2006, 08:21 PM

Quote:

Originally Posted by AstroJunk

Don't spend a cent till you've been out with us on a DSO or LPO night Dave - I see you're a fellow member of the AAQ. We have a very representative sample of scopes which are regulars in the field.

Play first - Pay later, that has to be the best advice ever!

@ AstroJunk

Best advice yet!

MarkN · #29 10-03-2006, 10:20 PM

"I already mentioned that the Meade Schmidt Newtonians were a poor choice as a lunar/planetary scope and not as good as a normal newtonian. The large 40% Central Obstruction, which reduces contrast, is one of several factors which contribute to this".

I see it now John, don't know why I didn't see it before. 'umblest apologies.

Mark.

AstroJunk (Jonathan) · #30 10-03-2006, 11:27 PM

Quote:

Originally Posted by DaveO

While I will primarily do visual work with it, I want to be able to move into some astrophotoghy as well in the future. Nothing obsessive (yet). I also need the scope to be portable, as 3 or 4 unfortunately placed street lights make observing from my house a pipe-dream.

SNIP
I My budget is $2500-$3000
/SNIP

How can we possibly cite eddie's permanent observatory as a benckmark here ($20-30K?) with many thousands of hours dedicated effort to get those results. Get back to the original requirement guys! Mainly visual with photography as a potential, not the other way round.

You may lose contrast with a schmit Newt, but with 10" to play with, it's not so bad. If 80mm is so great, why do we all own 10"+ scopes?

We're not all pro's here, some of us just dabble!

(Sorry for being a bore

)

[1ponders] (Paul) · #31 10-03-2006, 11:34 PM

You're not being a bore AJ.

All viewpoints are welcome.

Besides you know us imagers. We hate to see a potential candidate get away.

DaveO (David) · #32 26-03-2006, 12:21 PM

All

Thanks for all the advice, suggestions, counter-advice and so on! After much navel gazing, I finally made a decision.

On Friday I ordered a SkyWatcher 10" Newt on an EQ6 GOTO mount.

In the end I decided aperture was most important to me at this time. the cost was about $2700, which was well within the budget (if one conveniently excludes all those little "extras" one can start spending money on....).

However a telling factor was that the ED80's where "only" $600! My thinking is get the 10" now for DSO work, and but the ED80 later when I get more serious about the photographic work. The mount I am getting can deal with either scope, so I am set up in the short term with options for the longer term.

I'll post the outcome when I get the scope. Hopefull Brissy weather will improve by the time the scope gets here!

DaveO (David) · #33 26-03-2006, 12:22 PM

Quote:

Originally Posted by [1ponders]

Besides you know us imagers. We hate to see a potential candidate get away.

Possibly the most amusing and honest comment I saw in this thread!!!! Think of me as not so much getting away, as saving up for the REAL show!

acropolite (Phil) · #34 27-03-2006, 09:01 PM

Nice to see another one lured over to the dark side.

AstroJunk (Jonathan) · #35 28-03-2006, 08:33 PM

Quote:

Originally Posted by DaveO

Think of me as not so much getting away, as saving up for the REAL show!

Yeah, and us AAQ members don't settle for anything less than a 5" Tak!

Looking forward to playing with your new toy - and thanks for the clear sky's over Qld. I assume you putting in an order caused them. It's just a shame it has to cloud over as soon as the scope arrives, but thems the rules of astronomy.