Seeking advice on GSO RC 8" & HEQ5 PRO for Astrophotography

[Digital Artist]

Kindly be patient and read it and of course help me to decide

First thing first, i am newbie in astronomy and i don't have any telescope or mount what so ever but i want to do Astrophotography. But there are two problem:

1) I have limited budget and

2) There is no authorized dealer or shop for telescope where i live.

So i have to buy all the equipment from abroad in fact from Australia cause i have someone who lives there.

After researching about it on internet i realize that a HEQ5 PRO mount and GSO Richey-Chretien 8" telescope will be good just within my budget and as the budget is an issue for me I will use that telescope for visual usage for now as i will gather more money (God help me) for a camera (may be canon DSLR) i will switch to Astrophotography just like this guy (http://deepspaceplace.com/gso8rc.php).

Source for the equipment:

1) HEQ5 PRO ----- http://www.bintel.co...ctview.aspx����

2) RC-8" f/8 astrograph w/M-LRC focuser Aluminium tube ------ http://www.andrewsco...-section-10.htm

Now, question

1) what kind of Eyepiece do i need to have?

2) What kind and size of extension tube and/or focal extender do i need? (it seems it is needed as pictured in these websites:

http://deepspaceplace.com/gso8rc.php

http://www.cloudynig...hp?item_id=2006

3) Do i need right angle telescope eyepiece? If yes which one will fit with it?

4) Will any of this set will work with this telescope?------- http://www.bintel.co...27/catmenu.aspx

5) What else do i need? for visual now but switch to Astrophotography later.

6) Any other better options available?

As i have to import these things from Abroad i have to be just right so that i can use it right out of the box.

Please help me with your valuable advice.

Thanks in advance.

[glowjet]

As a newcomer to Astronomy I applaud your enthusiasm and the research you have done into the equipment you would like to obtain to eventually become involved in AP. I would, however, recommend that before you spend any money on Astro gear, especially as you want become involved in photography, to see if it is possible to obtain a copy of Steve Richards book "Making Every Photon Count" available through FLO see top of page, if you contact them I am sure there will be some way for you to obtain a copy to be sent to Bangladesh. I think most will agree that it is essential reading, as it will answer a lot of the questions you have raised, you may also want to amend your outlook on the Astro gear you eventually obtain. It is normal practice for new telescopes to come already kitted out with eye pieces and all essentials for visual use and I should get used to using it before embarking on the acquisition of further Astro equipment HTH

John.

[kirkster501]

Hi, the RC8 is a great scope alright but it is aimed mainly at imaging - it is an astrograph after all. Of course, you can use this scope for visual quite well but it is not optimized for that and if you want to be a visual observer first you can get something for a lot less money that will do a better job at visual than a RC8.

[Digital Artist]

Hi, the RC8 is a great scope alright but it is aimed mainly at imaging - it is an astrograph after all. Of course, you can use this scope for visual quite well but it is not optimized for that and if you want to be a visual observer first you can get something for a lot less money that will do a better job at visual than a RC8.

Thanks for your reply. I know there are better options for visual. But I want to buy it mainly for AP but for now i will use it for visual. However, can u give me little more advice on number 1,2,3 and 4 questions in the above.

[earth titan]

Hi there.

To answer the best I can:

1) You'll need more than one eyepiece I'm afraid. They all provide different levels of magnification due to their various focal lengths.

2) I'm unsure about this but you will need a camera adaptor (T ring) to allow fitting the camera to the rear of the scope. I think, from what you're looking at that you'll just need the adaptor and a workpiece - this is what is shown in the pictures you've seen. Most of the adjustment will come from the focuser.

3) You'll need a star diagonal (90') unless you want to spend your life on your knees looking through the EP.

4) Should do but be aware: Kits often contain poorer quality kit than you can buy singly.

5) You'll possibly need a focal reducer for AP with a DSLR, cos at f8 the length of shutter duration to get a goodish signal to noise ratio may not be optimum. This thwn brings in the question of spacers etc.

As for alternatives, I would go for a C9.25 which is much more of an allrounder but you will need definitely need a focal reducer to allow AP work.

You may also want to go for an NEQ6 straight away if kit is difficult to come by, as you may soon find the HEQ5 is overloaded when you add finders, guiders etc.

Typed by me on my fone, using fumms... Excuse eny speling errurs.

[ollypenrice]

OK, you know that an RC is not optimized for visual because of the enormous secondary. I would also say that it brings other disadvantages once you start AP.

AP is difficult. Starting imaging at long focal lengths makes it more difficult. Your guiding has to be better, the seeing has to be better, there has to be no wind... Imaging at slow F ratios makes it more difficult as well. You need longer exposures (which DSLRs don't like - I guess it is very hot where you live? If so DSLRs will like long exposures a heck of a lot less. A fast F ratio might be essential for you.)

RCs make it more difficult as well. They are tricky to collimate. Not impossible, but the difficulties and obstacles to a nice productive nights are stacking up... These budget GSO RCs are good value but they don't seem to be 'plug and play' instruments. You'll need to fiddle around to get them into shape, or so most people find. This is confirmed by the fact that several outlets are working on versions with the same optics but much better mechanical construction. You stress the import implications and this would make me wonder if an instument with a better QC track record might not be better?

I'd say that for DSLR imaging in the heat Bangla Desh you need a fast F ratio and a shorter focal length would be easier for a beginner.

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2277139556&k=FGgG233

[Gonzo]

Great post about the RC 6"

http://stargazerslounge.com/topic/171866-altair-astro-6%E2%80%9D-ritchey-chretien-review/

[johnrt]

Having owned a 6" RC for almost a year I would certainly not recommend one as a first purchase for astrophotography. They are, as Olly says, tricky to collimate and their long focal length and slow f/ratio require very long exposures which means good tracking and guiding. You will be right at the limit of an HEQ5 with the 8" RC, unless you are thinking of the carbon fibre tube version. Mine also came with a set of mechanical issues to iron out and took me the best part of my first year of ownership to get it suitable for imaging.

So what would I recommend? For the budget you would spend on the 8" RC you could get yourself a smallish (80mm?) fast ratio triplet refractor and matched flattener. This type of scope is the workhorse of most DSO imagers and will cover a range of targets all year round, they are lighter and the shorter focal length and faster f/ ratio much more forgiving. You can then always work up to an RC type scope once you have found your feet in AP.

Edited February 10, 2013 by johnrt

[Chris]

+1 for a faster easier scope, as said something like an ED80 Apo refractor with reducer flattener would be great and would invlolve zero collimation.

I've become a fan of Newtonians for dual visual and imaging purposes, fast f/5 Newt's are very popular because they are very cheap easy to collimate, and as said fast optically which means shorter exposures which as said previously DSLR's like.

Edited February 10, 2013 by starfox

[Digital Artist]

+1 for a faster easier scope, as said something like an ED80 Apo refractor with reducer flattener would be great and would invlolve zero collimation.

I've become a fan of Newtonians for dual visual and imaging purposes, fast f/5 Newt's are very popular because they are very cheap easy to collimate, and as said fast optically which means shorter exposures which as said previously DSLR's like.

Thanks for your reply. Can u see the link to let me know if it will do the job:

http://www.bintel.co....oductview.aspx

again do i need field flattener/ corrector if yes then which one will fit it?

Thanks again.

[Digital Artist]

Hi there.

To answer the best I can:

1) You'll need more than one eyepiece I'm afraid. They all provide different levels of magnification due to their various focal lengths.

2) I'm unsure about this but you will need a camera adaptor (T ring) to allow fitting the camera to the rear of the scope. I think, from what you're looking at that you'll just need the adaptor and a workpiece - this is what is shown in the pictures you've seen. Most of the adjustment will come from the focuser.

3) You'll need a star diagonal (90') unless you want to spend your life on your knees looking through the EP.

4) Should do but be aware: Kits often contain poorer quality kit than you can buy singly.

5) You'll possibly need a focal reducer for AP with a DSLR, cos at f8 the length of shutter duration to get a goodish signal to noise ratio may not be optimum. This thwn brings in the question of spacers etc.

As for alternatives, I would go for a C9.25 which is much more of an allrounder but you will need definitely need a focal reducer to allow AP work.

You may also want to go for an NEQ6 straight away if kit is difficult to come by, as you may soon find the HEQ5 is overloaded when you add finders, guiders etc.

Typed by me on my fone, using fumms... Excuse eny speling errurs.

Thanks for your reply. Your really take time to give answer to my every question. However, for HEQ5 pro my calculation was:

However, my calculation on weight was:

GSO RC 8" (metal) 7.5 kg

DSLR camera 1.0 kg

Orion Mini AG link http://www.optcorp.com/product.aspx?pid=210-16639

package 0.6 kg

Ring, plate 1.5 kg

Total 10.6 kg

Is the calculation correct or should i add something? Even though prescribed payload for HEQ5 pro is 15 kg but it is said that for AP it should be less than 10 kg.

Kindly give me your thought.

Thanks again.

[Chris]

Thanks for your reply. Can u see the link to let me know if it will do the job:

http://www.bintel.co....oductview.aspx

again do i need field flattener/ corrector if yes then which one will fit it?

Thanks again.

Hi,

The spec looks good:) Although I'm not familiar with the make I'm affraid? If its a portable imaging rig then a 150mm f/5 might be better because it would catch the wind less and it would be lighter, it has a 750mm focal length which will be easier to track the sky with and the field of view will be wider.

If I wanted a portable setup and an HEQ5 then I would go for the 150mm f/5, I have a 200mm but its on a permanent concrete pier and an NEQ6.

hth

Chris

Edited February 13, 2013 by starfox

[kirkster501]

Hi again,

I've had my ED80 rig for eight months (which equals three months in the UK weather) to get some AP experience and learn the ropes which I am slowly doing before I felt confident to have a go with a RC8. Only had one effort so far with the RC8 (again due to weather) which was a total failure for numerous reasons - most important of which is alignment of the mount needs to be VERY much more accurate due to the more "zoomed in" image scale you will get with the RC8. I have not even got on to guiding this scope yet or the fact that because I use a modded DSLR there will be more noise due to longer exposures. As Olly and Steppenwolf have both said before (and they are the experts) the ED80 hides a multitude of sins in your setup approach and equipment mix that at least get you the experience to get some good early results. Starting out with the RC8 you might become very frustrated and wonder what you have let yourself in for. I'd suggest a ED80 to start with and get an RC8 later. I really would. Under your clear skies you will love it. And you will keep it later as your widefield scope.

Steve

[Digital Artist]

Hi again,

I've had my ED80 rig for eight months (which equals three months in the UK weather) to get some AP experience and learn the ropes which I am slowly doing before I felt confident to have a go with a RC8. Only had one effort so far with the RC8 (again due to weather) which was a total failure for numerous reasons - most important of which is alignment of the mount needs to be VERY much more accurate due to the more "zoomed in" image scale you will get with the RC8. I have not even got on to guiding this scope yet or the fact that because I use a modded DSLR there will be more noise due to longer exposures. As Olly and Steppenwolf have both said before (and they are the experts) the ED80 hides a multitude of sins in your setup approach and equipment mix that at least get you the experience to get some good early results. Starting out with the RC8 you might become very frustrated and wonder what you have let yourself in for. I'd suggest a ED80 to start with and get an RC8 later. I really would. Under your clear skies you will love it. And you will keep it later as your widefield scope.

Steve

Thanks for the reply. Just to know-- as the RC is f8 a focal reducer is necessary for wide field imagery, Right? then if focal reducer is used to have f5 or f4 will it still have those problem that you mentioned?

[Jessun]

The most you can reduce the 8"RC to as far as I know is about f5.4 using the AP CCDT67 reducer. This leaves you with a focal lenght of over one metre still, so on paper you're a lot closer to the 0.6m ED80, but problems grow quickly with added focal length.

Even reduced, the 8"RC can't really be regarded as a wide field scope. The Orion nebula for instance just about fits on a APS size CCD.

/Jesper

[kirkster501]

Thanks for the reply. Just to know-- as the RC is f8 a focal reducer is necessary for wide field imagery, Right? then if focal reducer is used to have f5 or f4 will it still have those problem that you mentioned?

Hi there,

it isn't a specific Focal reducer as such made by GSO but some people have used third party ones with success. I have not as yet used one for my RC8 - I have only had it for three weeks or so and only had one occasion to use it due to our bad weather. As such, am not qualified to say. johnrt has used one though so lets see when he comes on line.

Steve

[LennyG]

I am a newby too, had a really cheap scope a few years ago till the dog crash tackled it. Decided to get serious (ish) and bought a GSO RC8 carbon and a SW HEQ5PRO. I am very happy so far using it for visual. I am improving my control of the mount manually as I am yet to get it aligned properly. Always seems to be 15deg out. Have checked time settings. The house blocks the SCP and there is a very bright streetlight near the front yard. Aside from that, all is good. Great views of Jupiter, bands clearly visible and on a good night the red spot too. Saturn looks extremely cold ! Can see bands reasonably well on average nights and have clearly seen the Cassini Division a couple of nights. I got the Baader mk4 zoom and Barlow so use the two small spacers that came with the scope and a gso quartz diagonal. Without the Barlow, one small spacer and the large one. Alpha Centauri looked nice tonight very clear to the south. With the Barlow (2.25) on,visual focus limits are reached at about 12 on the 8-24 zoom scale. As expected. Buying the zoom eliminated the guesswork in selecting eyepieces 

How deep does the rabbit hole go ?!  

Have a SW ED72 on the way with a TV 4x powermate asi air and 290mini, and a T48 spacer set to go between the 4x and my 7D. 6D mk1 next or asi 1600? Then a 35mm or there abouts wide field eyepiece. Thought about the baader 36 but there seem to be some bad reviews so $$$TV ?!

I am in the deep end, drowning in happiness, even though ‘they’ say start smaller. If you are patient go for it. Talk to Luke at Andrews Communications. Happy viewing.