Getting started with astroimaging

siovene · 02.10.2010, 11:23:37

Hello,
I hope you don't mind me hijacking your forum with a thread in English, but I couldn't write all these things in Finnish :)

So, I finally moved out from the center of Helsinki, to an area where the light pollution is a bit more bearable, and I would therefore like to renew my interest in astronomy and astrophotography.
I need some advice concerning the equipment that I need. I have been doing casual visual observations with my old 114mm newtonian on a shaky mount for many many years, so I think it's time to take the plunge and invest in some equipment to refresh this hobby.

I've been looking for Finnish stores on the Internet, and the only one I have found is VillenKello. Can anybody recommend some other places too, so I can compare prices and inventory? Or do you guys usually buy abroad from the Internet?

Anyway, as I want to start small, I thought I need the following things:

Equatorial mount: I was thinking of the SkyWatcher HEQ5 Syntrek (I don't need the GOTO because I'd use it from my yard, driving it from the laptop)
An imaging scope: I was thinking of a 80mm apochromatic, perhaps the SkyWatcher 80 ED DS-PRO
A guiding scope: some 70mm random refractor? Suggestions needed!
A guiding camera: I have no idea, I need suggestions!
T2 connector for my Canon EOS 450D. Also, some other connectors?
A way to put both the telescopes on the same mount. How do I do that? Is there a sort of forking dérailleur or something?
Other?

Can anybody please advise me with this? Thanks a lot in advance.

einari · 02.10.2010, 12:17:22

Hello, and welcome to forum.

Your thoughts sounds very reasonable to me.

Now , your questions.
There are couple other alternatives where you can buy astro gear in Finland.
The other is Ylva Astronomia and the other is Ursa.
Many of us use foreign stores too (ie Teleskop-Service, Modern Astronomy etc).

HEQ5 Syntrek with 80mm apo sounds a good plan.
70mm refractor can be used as a guide scope.
Some (like myself) use also bare 7x50 finder as a guide scope (it's good when using 1000mm+ focal legth imaging scope).
Others use off axis guiding.
If you use some refractor you need some kind of duomount so you can set scopes side by side.
Guiding camera: I use QHY5 which is good&inexpensive. There are other variants of the same theme (ALCCD, Orion Starshoot Autoguider).
Some use modified webcams and others use more expensive cameras like Starlight Lodestar, QHY6 etc.

Camera connector: Maybe the best way is to use 2" (or 1.25") to T adapter, like this:
http://www.teleskop-express.de/shop/index.php/cat/c130_Astro-Imaging----Adapters----Focal-Photography.html

siovene · 02.10.2010, 13:28:47

Hi, thanks for your answer. A follow-up:

So if I get this:
https://www.teleskop-express.de/shop/product_info.php/info/p200_Adaptor-2--to-T2---low-profile.html

it means that I don't need this?
https://www.teleskop-express.de/shop/product_info.php/info/p194_T2-Adaptor-for-CANON-EOS-Cameras.html

Thanks!

Lauri Kangas · 02.10.2010, 13:42:01

Hi again Salva,

You'll need both, they screw onto each other. The performance of 80ED is greatly enhanced when using a field flattener, since the image plane the scope produces is normally somewhat curved. I've experimented with William Optics 0.8x reducer/flattener mk. III. Telescope Service also deals their own flattener design and even Sky-Watcher has one (inexpensive) model out today. WO and SW flattners replace the first adapter you linked (T2 thread to 2"), the TS flattener screws onto it.

Otherwise the 80ED is a great choice and this forum has lots of great stuff imaged with that mount/scope combination. I've also been using a 9x50 finder scope as a guider with QHY5 camera and had great results. Using a small scope is surprisingly accurate and makes most mechanical flexure problems (with the guiding and imaging scopes bending in different directions) magically go away. Adapters for this are available at KW-Telescope and Modern Astronomy.

Lauri Kangas · 02.10.2010, 13:51:42

And something regarding the mount: HEQ5 pro using computer control is in my opinion the most cost effective tracking available. The Syntrek version is the same thing as the more expensive SynScan but without the hand controller, which is replaced by a computer. Just be sure to avoid the older HEQ5 versions with just slow stepper motors, they're not capable of anything else than simple tracking.

You can't drive the mount directly from a computer but need to use a RS232->TTL converter in between. These are sold in astro shops under the name EQDIR but the best option is to buy a converter chip built inside a USB connector from FTDI and attach the RJ45 connector for HEQ5 at the other end. Works really well compared to using a separate EQDIR module with a clumsy USB to Serial adapter.

siovene · 02.10.2010, 14:05:17

einari · 02.10.2010, 17:13:43

Looks pretty good to me.
However I personally would change colour guiding camera to mono.
It's more sensitive so more stars to choose from.
But if you would like to do easy planetary imaging then i think you can do with a colour cam too.

I'm not sure if you can screw reducer directly to Evostar scope.
Suspect it will but maybe someone (Lauri) can confirm.

Lauri Kangas · 02.10.2010, 17:31:03

That cable is for the Ursa Minor connecting system. I'm not familiar with it and can't remember if it was compatible with EQMOD or not. IMO EQMOD is the way to go, best piece of astro software I've come across. An RS232 version of EQDIR is sold here http://www.store.shoestringastronomy.com/products_eq.htm or a direct USB version here: http://www.iankingimaging.com/show_products.php?category=165

However those are way too expensive since EQDIR is nothing but a TTL converter. I ordered a converter from here: http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm
I actually chose the PCB version and soldered a piece of an ethernet cable to it, the thread is found here http://foorumi.avaruus.fi/index.php?topic=6170.msg56182#msg56182

Regarding your shopping cart, I might think of a piggyback mount since using a side by side mount with large scopes is prone to flexure. However the piggyback is too if you use fine tuning rings like those on your link. In my opinion a 500mm focal length guide scope with the 1/2" sensor of QHY5 doesn't need any direction control, there's always guiding stars available in the FOV.