Suggestions for Astro scope + mount

agivney · #1 04-07-2014, 11:33 PM

Hello All,

I am an experienced armature photographer and wish to get into astrophotography. I am just a bit lost as to what type of scope and mount I should buy. I already own a Nikon d4 and Nikon d5100 (converted to infrared).

At this stage I am looking at:

Celestron CGEM DX Computerized Equatorial Mount and Tripod - 91528
http://www.highpointscientific.com/t...d-tripod-91528

Explore Scientific 80 mm Essential ED Triplet Refractor
http://www.highpointscientific.com/t...s-es-ed0806-01

and some type of auto guider.

Please give me your thoughts and ideas!

Retrograde (Pete) · #2 06-07-2014, 01:54 PM

Hi agivney & welcome to IIS.

It sounds like you are on the right track with an ED80 & a decent GEM but I can't offer any insights on that particular combination. A good mount is key and a focuser that doesn't slip with one of your DSLRs attached is also very important.

What sort of objects do you wish to photograph? Deep Sky or planets?
Where are you located (which country)? If you can tell us a bit more about your situation then it might be easier to advise you on specifics.

Astrophotography can be frustrating at times whilst you are learning the ropes but also very rewarding. Enjoy the journey

agivney · #3 07-07-2014, 01:00 AM

Thanks for your encouraging words. I am actually located in Sydney Australia. I have been doing some further research and am steering toward the same mount, but a different scope.

I am considering getting the Celestron 1100 HD f10, and initially using it with the Starizona Hyperstar, which will give me a focal length of around 460mm with an aperture of f2 (that should make my early attempts at astrophotography more manageable). Of course, when I remove Hyperstar I will have the normal Celestron scope readings. I will also be purchasing an auto guider.

I am heading toward deep space photography but I also want the option of viewing at high magnification and eventually when I get the hang of things photographing distance objects. The more flexibility I can have the better.
I plan to purchase everything in about a month from now after hearing what people have to say. I am also doing a lot of research concerning during this time how to align the scope, and making myself familiar with objects in the sky and the concepts of astrophotography etc. There is a lot to learn!

By all means give feedback!

Thanks.

Retrograde (Pete) · #4 07-07-2014, 02:21 PM

Hi - that's a bit of a change. Sounds like an imaging platform with lots of potential and flexibility though.

Have you thought about how well the mount will handle the larger OTA?
Also if you plan to use one of your DSLRs with Hyperstar will that cause additional central obstruction?

I'm just throwing up some points for you to think about - doesn't mean either of those will necessarily cause an issue. It may be worth starting a new thread on the "Equipment Discussions" sub-forum where a larger number of people with direct experience of that mount and/or OTA will see your plans and hopefully be able to advise of any pitfalls or recommendations.

rustigsmed (Russell) · #5 07-07-2014, 04:05 PM

hi agivney,

welcome, and am loving your enthusiasm!

interesting idea going with the 1100 HD -i'd probably advise against it, while it does seem flexible; when at f10 it may take some taming to guide at such a long focal length, and on the flipside imaging at f2 will be challenging also as you will quite easily go out of focus due to the sensitive nature of f2.

these aren't surmountable issues, however you should be aware that it is frustrating enough learning astrophotography with a forgiving system. so depending on your personality it could turn you off astrophotography for good - and we don't want that...

as pete mentioned, go with the best mount you can afford. i'm not familiar with CGEM and don't know if it is appropriate for (deep space) astrophotography with an 11" SCT+cameras it would however likely be fine for visual and planetary with that weight though.

other things to consider - as pete said, a high quality focuser such as a moonlite or feathertouch and possibly an off axis guider with quality guide camera (eg lodestar or QHY5 II).

a good way to know what type of system to get is to work backwards from photos. see ones you like and take note of the system used to acquire the image. there is no perfect scope that does everything, I like largish newts as i consider them the closest thing to an all-rounder (and cheap). But saying that I foresee a nice widefield refractor AND a large Ritchey Chretien for long focal lenght work in my not too distant future.

best of luck.

Rusty

Camelopardalis (Dunk) · #6 07-07-2014, 05:07 PM

Welcome to Ice in Space agivney!

The CGEM DX is a beast of a mount - probably borderline portable for a lot of people - so I'd recommend you get to see one before you buy. Personally, I like the Celestron handset software, the star alignment is easy and the all-star polar alignment is effective. But it's quite an expensive mount in Australia, so if you're certain you want that size of mount it might be worth considering the Skywatcher EQ8 or Losmandy G11 also.

Regarding the scope...the C11 has a long focal length and the Hyperstar itself is reasonably pricey. At around 560mm focal length in f/2 configuration, you could easily reproduce this with other scopes that are less of a handful, like 80-100mm apo refractors. Sure, you might lose resolution but it might be a less frustrating place to start, and the mount you could get away with could be smaller and lighter. The secondary obstruction is about 95mm across, so your camera will extend a little past this but not a huge amount.

I use a C11 Edge HD for visual and I've been experimenting with capturing planetary sequences and like it a lot...it's quite compact for its aperture, it's just the mount to carry it - I use an EQ6 - is big and heavy, but a lightweight compared a CGEM DX and the alternatives! I haven't tried DSO photography with it, although I have experimented with a C8 on the same mount for this.

agivney · #7 07-07-2014, 11:19 PM

Thank you for your feedback, so many things to think about!

A few thoughts:

At this stage I will probably purchase my gear in one batch from the U.S, at the site, http://www.highpointscientific.com. I would like to buy it from A.U, but the price difference is just too much. Also, from what I can tell, there is a 2 month waiting list even if I buy from A.U for some of this equipment, in other words, they appear to be doing what I am doing! Ground shipment is free.

I am starting to see that my Nikon DSLR may not be a good option mainly due to high noise, high operating temperature, information clipping and its shear size, it simply will be more finicky than a dedicated scope camera, so I may also buy a one of those. At this stage I am looking at the Atik 490Ex Mono, with a manual filter wheel etc which apparently works well with the Hyperstar.

I did not think of the f 2.0 focus difficulty, but I think I can overcome this with patience.The f2.0 also has some major advantages, such as much less exposure time. I think my biggest issue initially will be tracking.

I do like the idea of using the scope at high magnification for visual work.

I will look into the focuser, but will that be necessary if I get the Atik 490?

Regarding the mount size, I think I will certainly go for that, knowing from my own long exposure photography experience, the mount is a deal breaker and I do not wish to be buying a bigger one anytime soon. The mount can apparently handle the 14" model. The size is fine, I am not a small person by any means (6.3.5") and the weight is manageable for myself. I own a Caddy Van and can transport it in that.

At this stage I am looking at around 8k for the setup from the U.S. By nature, I like the technical side of things and computer processing, I realise it will take some time to get the hang of this setup. I know from past experience, if I get something easier and less powerful, I will within a year get this rig anyway.

Thanks again.

Camelopardalis (Dunk) · #8 08-07-2014, 08:36 AM

Ground shipping from the US is free?

Also remember that you will have to pay duty and GST when it arrives in Australia.

Larryp (Laurie) · #9 08-07-2014, 08:39 AM

Quote:

Originally Posted by Camelopardalis

Ground shipping from the US is free?

Also remember that you will have to pay duty and GST when it arrives in Australia.

Plus currency conversion and international freight. GST is applied to the cost of the goods including freight. Free ground shipping would only apply in USA-no use to you.

rustigsmed (Russell) · #10 08-07-2014, 09:56 AM

Quote:

Originally Posted by agivney

Thank you for your feedback, so many things to think about!

A few thoughts:

At this stage I will probably purchase my gear in one batch from the U.S, at the site, http://www.highpointscientific.com. I would like to buy it from A.U, but the price difference is just too much. Also, from what I can tell, there is a 2 month waiting list even if I buy from A.U for some of this equipment, in other words, they appear to be doing what I am doing! Ground shipment is free.

I am starting to see that my Nikon DSLR may not be a good option mainly due to high noise, high operating temperature, information clipping and its shear size, it simply will be more finicky than a dedicated scope camera, so I may also buy a one of those. At this stage I am looking at the Atik 490Ex Mono, with a manual filter wheel etc which apparently works well with the Hyperstar.

I did not think of the f 2.0 focus difficulty, but I think I can overcome this with patience.The f2.0 also has some major advantages, such as much less exposure time. I think my biggest issue initially will be tracking.

I do like the idea of using the scope at high magnification for visual work.

I will look into the focuser, but will that be necessary if I get the Atik 490?

Regarding the mount size, I think I will certainly go for that, knowing from my own long exposure photography experience, the mount is a deal breaker and I do not wish to be buying a bigger one anytime soon. The mount can apparently handle the 14" model. The size is fine, I am not a small person by any means (6.3.5") and the weight is manageable for myself. I own a Caddy Van and can transport it in that.

At this stage I am looking at around 8k for the setup from the U.S. By nature, I like the technical side of things and computer processing, I realise it will take some time to get the hang of this setup. I know from past experience, if I get something easier and less powerful, I will within a year get this rig anyway.

Thanks again.

I've looked up the CGEM DX and its payload is only 22kgs. If you're loading up an 11" SCT I'm really not sure how good it will be at anything other than planetary or really short exposures - the general rule is for astrophotography you should only load up around half the mount's weight capacity. As for a 14" SCT it may hold it (20kgs) but i would question it's useability for anything other than visual. You should probably consider an EQ8 or similar instead.

I'm sure you are aware but just to be clear the point retrograde was raising with the DSLR (or any other large CCD) and the hyperstar setup is that the bigger the camera the more it blocks the in coming light as its located in 'front' of the telescope and not the back. A filter wheel is out of the question teleskop shop in germany has a filter 'draw' system that may work for you.

definitely be careful of importing it is likely to be costing a lot more than it appears.

good luck,

Rusty

agivney · #11 08-07-2014, 10:38 AM

Thanks for the information, it is very helpful. I will have to seriously rethink how I will go about this and what I should get.

I can verify, that when I did enter shipping for my address to Sydney, provided I sent it via slow freight, there was no charge. But that does sound a bit too good to be true. I have written to them to check this.

GST, currency conversion; yes, it would add at least 16% to the total, if shipping is indeed not free, then it certainly does add up.

It certainly does pay to get other people's perspective!

jjjnettie (Jeanette) · #12 08-07-2014, 01:15 PM

The ED80 you were originally considering is the workhorse of the astro imager. It's perfect for cutting your teeth on and given the number of objects up there that fit nicely into it's field of view, it should keep you busy for a year or so.
Down the track, once you've mastered drift aligning, guiding and processing, then consider your upgrade to a larger scope.
The learning curve for astro imaging is a long and frustrating one. There are no short cuts. Each step must be taken as it is the foundation for the next, and without that foundation, everything crumbles. But if you take joy in the details, and love to fiddle with techy stuff, this is the hobby for you.

alistairsam · #13 08-07-2014, 02:22 PM

hi,

have you considered a CarbonFibre RC8 or RC10? that will give you the long focal length and if you use a reducer, you can get it down to an F6 I believe. the CCD67 reducer although not meant for this, works quite well. you just need the right flattener.

As for the mount, why the CGEM? do you know what its raw PE is? I think it is worse than the NEQ6. I'd suggest checking that. you can correct via PEC though but you'll need good PE data.
The G11 family is the next step up and you'll have to see if it fits in your budget.

I'll strongly recommend an OAG if you're not going with the Hyperstar. I have no idea if it can be used with the Hyperstar, but an OAG does away with all the flexure issues of a guide scope.
you'll need a sensitive guidecam. the LodestarX2 is amongst the best around, not sure how the STi stacks in comparison to the X2.

as for F2, it can be challenging and objects rather small. an F4 to F5 is the sweet spot for speed and magnification or object size.

or you could look at a triplet apo and use it with a reducer.

Cheers
Alistair

astro744 · #14 08-07-2014, 03:03 PM

Note you wont get local warranty if you buy from overseas unless the manufacturer has made such an arrangement with its authorised re-sellers. So if something goes wrong you will have to ship back to the place of purchase.

cometcatcher (Kevin) · #15 08-07-2014, 05:34 PM

I'm not sure whether we should be chucking you in the deep end or not! (Lest you drown). Regardless of photography skills, astrophotography is a steep learning curve.

What sort of telescope skills to you presently have? Have you used one for visual?

Your D5100, is that IR converted or full spectrum? IR in AP is not that useful, although there is one fellow that does some IR. The D4, now that's a capable camera. One of the best DSLR's one could use for AP, though a dedicated astro mono CCD would be better, but completely different to use.

Skywatcher make a great line of refractors if you want to go down that line, from the ED80, to the ED100 and ED120. They also make Esprit APO triplets. I'm presently driving an ED100, probably more to do with budget otherwise I would have the ED120. Refractors are so darn easy to use, no mucking about with collimation, no adjustments, fast temp settling time.... They are just like using a big tele lens. The Nikon D4 and SW 120mm refractor would be a good combination.

But then GSO make really good fast Newtonian astrographs. Who wouldn't like 1000mm focal length at F4? Being a reflector they need collimation, and fiddling with, but if you can live with that they are excellent bang for buck.

Keep in mind that learning curve though. The bigger the scope the trickier it will be to tame.