CG5 or HEQ5PRO or EQ6Pro? C8 tube or 10" Newton?

[Poita]

Hi, I've got an extremely tight budget and am getting back into stargazing after about a twenty year break!

I have my old, old Celestron C8 and wegde and a couple of eyepieces, it is a bit dusty, but still functions and the kids and I have had some fun looking at the stars and using the ipod touch starwalk app (excellent!!) to find things in the night sky.

I'm looking to take some photos, I like the moon and planets, but think with the planets I may tire of taking photos as there are only a few to pick from :)

So I'm thinking deep sky and have a few questions.

I can afford a CG5 mount or for a little more a HEQ5Pro that comes with a 10" Newtonian scope ($1400) . Or for a few hundred more I can get the EQ6Pro on its own.

Can I use the C8 tube on any of these mounts, or is it two heavy for the cheaper models?

It a 10" Newtonian any good for photography? Would I be better off getting the 10" + HEQ5Pro and selling the old C8?

I have a Nikon D90 DSLR and a T-Ring mount for it to suit the Celestron.

I also happen to have a Toucam Pro webcam that we used to use for Skype and would have the basic skills to convert it for use as a camera for the scope.

Where should I go from here? I've read heaps about astrophotography, and it looks bloody difficult but rewarding, I'd like to take photos with the kids, using the DSLR and the Toucam and maybe save up for a better camera in a few years. I have a current laptop.

My total budget is around $1600, I'm a single Dad and can't afford any more than that. Other than the mount, and the gear I already have, what else would I need, I don't want to suddenly find out there is another $500 worth of kit that I then couldn't afford. Any help really appreciated.

[mswhin63]

I am considering the same options for my HEQ5Pro as well, I am considering maximum 75% weight of OTA compared to weight limit. This is to allow for camera gear and other factor that can add to overall load.

Carbon Fibre will help.

Consider carefully second hand gear but carefully.

[Gem]

If the budget is tight and your C8 OTA is in good condition: keep it!

If you want to do photography, aperture is less important than your mount quality. Make sure the mount you get is working well under its payload capacity.
Having said that, you need to be able to easy carry the set up you have unless it has a permanent shed/observatory.

[Poita]

The capacity on the HEQ5Pro is 14kg? How much under that would make it still usable for astrophotography?

I can probably setup permanently in the back yard, skies are pretty good even in town out here, but it would be nice to be able to take it all out for a really dark night, as you don't have to go far here to get black skies (I'm near Gulgong NSW)

Would a 10" newtonian give better eyeball viewing than the C8 SCT?

The C8 is okay, the front glass is a wee bit clouded, and the collimation is out, but I guess both of those could be dealt with. I'll have to weigh it and see what it checks in at.

My understanding is that if I wanted to do deep sky imaging, I could mount the Nikon D90 SLR piggy-backed on the telescope, but that I'd also need another scope if I wanted an autoguider? Or could the C8 be that scope if I was using the DSLR with normal lenses?

Is it possible to utilise the C8 with a webcam in the eyepiece socket and the laptop as an autoguiding system, or do I need to purchase an 'autoguider' as a separate entity?
Sorry for all the questions, I don't have anyone local that I know of to bounce ideas off, and I read a lot of books and forums but when it comes to a specific setup on a budget, I find it hard to decipher.

Cheers

-Pete

[renormalised]

Hi Peter and welcome to IIS:):)

Ok....how old is the C8??. I'm asking this because the really old versions may not have mounting holes underneath to attach doveplates to. Although, you can carefully drill and tap holes for these, anyway. In any case, if you buy the EQ6 mount, the weight of the C8 won't matter so much as the EQ6 can handle upto 20kg. The old scope won't weigh anywhere near that. Andrews (http://www.andrewscom.com.au/site-section-10.htm) is selling the EQ6 for $1399. You'll need a Vixen style dovetail plate to attach to your scope to the mount.

For imaging DSO's, seeing that the C8 runs at F10, for many targets you'll need a field flattener/reducer to fit them into the FoV (Field of View). A 0.63 or 0.33 reducer would do just fine. They reduce your focal length (FL) from F10 to F6.3 and F3.3, respectively. Though quite a few targets are better at the native FL or even longer (the planets, lots of galaxies, Planetary Nebs etc). For those, a good barlow and/or Powermate will do. You have the T-Ring already, which is a bonus.

Use your Toucam for the Moon and planets, that's what it's good for. The DSLR use for the DSO's.

As for a guider, you can get an Orion autoguider package for $420 from Bintel (https://www.bintelshop.com.au/welcome.htm), as well as the EQ6 cables and such to connect the mount upto your computer. EQMOD software can be had from the site (http://eq-mod.sourceforge.net/).

Best thing to do is if you can't afford it all at first, just save up and buy the bits over time. You'll need to gather the software (much of it free) first, plus read up on taking piccies and asking questions here of those of us that take piccies to learn what to do.

If you were going to do piggyback pics with your camera on the scope, you could guide through your C8 and take widefield piccies with your camera. You'll need another mounting plate on the top of your scope to attach your camera, or a mounting bracket for a camera that fits the finderscope mount.

There's quite a few bits and pieces you need to set yourself up, so it'll take a bit of time to gather them all. But in the meantime, you can use the Toucam to take piccies of the planets and the moon quite readily with your scope as it is and a barlow/powermate to give the image scale you need to take good planet piccies.

[Poita]

I'm not sure how old my C8 would be, probably bought it in the late 80s, definitely before 1992.
I'll check for the holes, I do tech support for a local CNC machine shop and engineering firm, so they could help me out with that if needed.

[Osirisra]

In your first post you said you have a wedge for the C8, you could save the money and just use your existing setup to take DSO's and planet pics. The knowledge and experience will give you more of a idea on the direction you would like to take and time to save up more loot.

[Osirisra]

..and the EQ8 is coming :P

[Poita]

I have a wedge, but not a mount. And I have nothing to do any guiding or tracking with. This is an old mechanical jobbie. The cost of a sturdy enough tripod and associated gear would seem to make it not worthwhile as far as I can tell. I have taken eyepiece projection pictures of the planets back in the early nineties on hypered film etc. but was never happy with the results.

My plan was to modify the toucam and play with the celestron (just sitting on the concrete path) with it whilst I was learning, but I have around $1600 now, that I can justify spending before June 30. I'm unlikely to have that money again in the next 5-10 years, so this will be a one off money wise, and I want to spend it wisely.

[Osirisra]

Ah I see, no mount makes it a bit difficult for sure. The EQ6 would surely do the job nicely and give you a good platform to work from later.

You might also be able to get a cheap second hand or new Celstron goto fork mount for the C8 and wedge that would give you cash left over for other goodies like guiders etc.

[RobF]

You should NOT put a 10" Newt on a Heq5Pro. Plenty of threads about that sort of thing in Ice. Too much weight. You should also read up on the peculiar challenges of imaging with Newts (short back focus, collimation which is quite fine on 10", etc).

[Poita]

I didn't know I could replace the fork with a celestron goto one. I'll look into that as an option.

It appears the HEQ5 would be solid enough for the C8, but not for anything heavier, am I right in that statement? Would it take the C8, and the photographic gear? I know that the EQ6 would be the better long term solution, but I am unlikely to ever be able to afford a bigger OTA.

RobF, thanks for the confirmation that the HEQ5Pro wouldn't be sturdy enough for the 10" Newtonian.

[Poita]

Okay, my current plan is to:
1) Clean and collimate the C8 and test it out and see if it is in good shape.
2) Purchase a $1099 HEQ5Pro, or if anyone has anything for sale or other suggestions in that price range I'm open to it!
3) Work out how to mount the C8 tube on the HEQ5Pro.
4) Get to know the telescope on its new mount with some night time viewing and practice alignment technique.
5) Modify my old Toucam for use with the C8
6) Get some sort of piggyback mount for the Nikon D90 (any suggestions?)
7) Attempt some manually guided photography using the C8 as the guidescope and work out what else I need to buy.

Am I on the right track? Will the HEQ5Pro be sturdy enough for the C8 Tube and DSLR and assorted goodies?

What else would I need for starting out with photography as a 'must have'

[RobF]

If you're going to do long exposure deep sky stuff sometime Peter you'll want to get guiding going eventually. I find there's lots of convenience and functionality using a 9x50 skywatcher finderscoper (modded) with a guidecamera. You could potentially get such a thing going with you ToUcam initially. I'm just not sure if it would be ok for guiding at 2m focal length (works well enough for my 1m FL). INitially you could get reasonable results just limiting subs to 30sec too, if polar alignment is pretty good.

[Poita]

I'd love to get autoguiding going, but it seems the most complex part and I only want to purchase gear once, so I thought I might be better off getting to know everything else and reading more and asking more questions before deciding on a guiding solution.

I'd be happy to purchase the guiding gear now if someone could recommend something that would last me a good long while. I'm fine with being tethererd to a laptop, mine gets about 9 hours out of its battery if I turn off the wireless etc. and usually power will be available as my backyard gets fairly dark skies.

The good CCD cameras really are astoundingly expensive aren't they!

[renormalised]

Your C8 with a .63 or .33 reducer/flattener could be mated with an Atik 383L camera for $2500 (that's a camera with the KAF8300 8.3MP chip) or an Orion Parsec 8300 camera for the same cost. A QHY8-L (6MP) will set you back $1500. The QHY10 (10MP) is about $2500.

Even an Atik 314L + (1.4MP) will give you great shots for only $1650, if you want to image at the native FL (which its pixels suit better than the others).

An autoguider....you can get a package from Orion (sold at Bintel) for about $420 with the scope and guider. If you're going to guide at the native FL of your scope (2000mm) you'd be better advised to get an OAG (Off Axis Guider) and guide through your main scope. The reason being trying to guide with a scope and guider on top of the main scope, you can get too much flex and lose guidance too easily when trying to keep an object in your main scope's mirror for imaging. You can lose tracking too easily and at long FL the objects slip out of view quickly. Also, you're more likely to get the object you want to image and your guide star in or near the same FoV at shorter FL's, due to the much wider FoV. Best, really, to keep things nice and easy....run at a reduced FL and guide through a scope/autoguider combo. Much more forgiving. Less worries with flex stuffing things up and easier to get a guide star.

[Poita]

Thanks so much for all the info Carl, Just to translate into Poita Speak to make sure I get it... :)

FL = Focal Length = 2000mm for my C8.
Which means it is like a monster zoom lens and has a very small FOV (Field of View)

So trying to track through it, I'll have buckleys that there will be a guide star close enough to what I am imaging. So I'd be better off with a small guidescope and guider to attach to the C8.



My best bet would be to get a guider pack from bintel that has a guidescope (Orion Mini Autoguider Package?) and a CCD autoguider thingy and I attach that assembly to my scope, and interfaces to my mount/computer?

Then I can either strap my DSLR with lens onto the C8 on the mount and take pictures of the sky that way, use the Nikon T-ring and extension tube to do eyepiece projection for planets etc. and can buy a CCD camera to start getting fancy.

If I want to stay at the 2000mm then a lower Megapixel camera would suit better like the Atik 314L.

If I want to shortern my focal length and widen my field of view, then a higher megapixel camera would be an option.


Have I got it right?

[renormalised]

You can track and guide at 2000mm, if you use an OAG and a sensitive guider. But it can be hard finding guide stars for some objects and it's not as tolerant of guide errors as a short FL and wider FoV...which will also be brighter per unit area. If you decide to run a guidescope with your C8, you're much better off lowering the FL/FR using a reducer-flattener. Bring that 2000mm down to something a bit more manageable, like 700-1500mm.

You can also use an OAG on a short FL scope as well. The good thing about an OAG is there's less weight on your mount (no guidescope etc) and no flex in the guiding (if setup properly).

Why the Atik is better for the C8 at 2000mm is because it's pixels size is larger than the other cameras I mentioned. It has 7.4micron pixels, the others range from 5.4 to 6microns. Larger pixels mean more sensitive to photons and usually larger full well capacities, which means they can gather more photons in and produce more charge in the electron wells of their p-n substrate without blowing out the image, especially on bright objects like some stars or planets. Plus you have to be careful of either under or over sampling the pixels. That's why you try and match your scope's aperture and FL to the camera. Go and have a look at this....CCD University (http://www.ccd.com/ccd113.html).

You've basically got it right, though.

Although, you can get chips with lots of large pixels e.g. KAF16803, KAI11000, KAI4000/4022, KAF6303 etc. They all have 7-9micron pixels. However, they're much larger than the little Sony ICX285AL in the Atik314L+ and cost considerably more...both as chips and as setup in the cameras. For example, the Atik314 is about $1650, the Atik11000 (using the KAI11000 chip) is about $6500 for the OSC version.

[renormalised]

If you want to see how various CCD's stack up with various scopes, download this program...

CCD Calc (http://www.newastro.com/book_new/camera_app.php)

It will allow you to have a look at the FoV's of the various CCD's in different scopes, when compared to the various objects you might want to look at. Very handy bit of kit. You can also add your own camera/CCD combo and see how it measures up as well.

[EddieDog]

Peter, eBay seller whom I have delt with has http://www.ebay.com.au/itm/Celestron-Piggyback-Camera-Mount-NexStar-SE-Telescopes-/230639512179?pt=LH_DefaultDomain_0&hash=item35b32faa73 piggyback mounts that might work with your scope. I got one for my 6Se works fine for my Olypus E500

eddie