Which scope would you pick?

[pringlepowell]

Excuse the ignorance, but I still can't see how I can attach the guide camera to a finder scope. It's not as though my 9x50 finder has a 1.25" eyepiece for attaching the QHY5 to, plus as Ollypence says, with a Newt an OAG would be more in line with the mirrors and not move. Aaargh!!

[tonedeaf]

like this...ok that´s a very russian solution...in my case rather polish

i hope that the cam is close enough to focus stars....(i could get a focus at trees 3-5km away, with around 1-2mm left)

if not i have to shorten the tube...or build a new casing for the pcb with the chip

[RikM]

http://www.modernastronomy.com/accessories.html

You replace the standard screw-in eyepiece on the finder with one of these adaptors and then screw the QHY5 onto that.

[pringlepowell]

As usual I think the astronomy shed video wins the day, the finder-guider is a good cost saver and looks to work well. I'm a little dubious at being able to stop the finder moving when the mount slews, but we'll see how I get on.

[PARTY MARTY]

To honest with you pringlepowell! It keeps it's position well, the only drama you'll have is to get the finder into focus, what I do is I wait till it's dark, when it's a cloudy night! Here I connect the finderscope and guide camera connect everything up except the ST-4 cable, run up PHD Guiding and set the loop function and set at 0.05 secs for starters will give you a live image, then I try and find an object which is more than a 1km away then (usually a street lamp), then once in place I just keep screwing the finderscope objective lens back and forth until my image shows focused. Then I'll somewhere a little further and do same again! You should be near focus once the time to really set up for imaging, your stars shouldn't take long to focus!

It's alway's best to do a dry run first, plus you'll that your guide scope set is working properly as well!

[tonedeaf]

as marty said....dry runs!

that saves a lot of time (every time i write a lot this comes to mind -> http://hyperboleandahalf.blogspot.co.at/2010/04/alot-is-better-than-you-at-everything.html)

now back to, where was i...

...ah...it saves a lot of time, precious time needed when the skies are clear

[PARTY MARTY]

Hi Pringlepowell! Just to get you an idea of how much chip size you would get from your reflector and DSLR, you get the entire Andromeda Galaxy and it's companion. This image was taken with my 8" F4 Quattro Coma corrector and my QHY8L (25x300secs, 10x150secs, 15x60secs, 10x300secs darks, 15 flats and 10 bais framesall stacked in Deepsky stacker and final processing in Paintshop pro X5) which is slightly smaller chip than a DSLR ccd would be! This an incredible field of view! That's why think you should keep your reflector, upgrade a Coma corrector and get into Autoguiding with a finder scope and you'll get results like this! No messing and you'll get superb results! :icon_biggrin:

[ollypenrice]

As long as you don't get any mirror movement a separate guidescope will be fine. You may or may not get any. It depends on the individual scope and the individual night. Well worth trying the finder guider first, though, because OAGs are a bit of a faff.

Olly

[ollypenrice]

Hi Pringlepowell! Just to get you an idea of how much chip size you would get from your reflector and DSLR, you get the entire Andromeda Galaxy and it's companion. This image was taken with my 8" F4 Quattro Coma corrector and my QHY8L (25x300secs, 10x150secs, 15x60secs, 10x300secs darks, 15 flats and 10 bais framesall stacked in Deepsky stacker and final processing in Paintshop pro X5) which is slightly smaller chip than a DSLR ccd would be! This an incredible field of view! That's why think you should keep your reflector, upgrade a Coma corrector and get into Autoguiding with a finder scope and you'll get results like this! No messing and you'll get superb results! :icon_biggrin:

That's not the entire Andromeda galaxy! You've chopped loads off each end! Good result, though, and a good advert for the Quattro. To get it all on a DSLR chip you'd need a focal length of about 500mm, I'd say.

We had to mosaic it; http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-FGgG233/0/X3/M31%20LES%20OLLY%20TOM%20TEC%20CORE-X3.jpg

Olly

[PARTY MARTY]

Olly as you said about mirror movement, to be honest with you I've never come across that problem with the Quattro at all even when I push 10 mins exposure times, it is a imaging reflector after all, but might be a problem with some reflectors!

[PARTY MARTY]

Thanks for the comment on the image Olly! This was slightly chopped at the sides a bit, this exactly a cropped image, I had to trim the edges a bit that what I hate those image lines you get after image is stacked! But saying that to this M31 is good field of view, and who knows what a DSLR is capable off!

[ollypenrice]

Olly as you said about mirror movement, to be honest with you I've never come across that problem with the Quattro at all even when I push 10 mins exposure times, it is a imaging reflector after all, but might be a problem with some reflectors!

Fair enough, and if it ain't broke don't fix it. To avoid distorting the mirror by pinching it is usually left with a tiny amount of play, an amount which will vary with temperature. This is why mirror flop is always a possibility. But if it isn't affecting you then that's great. The reflector we use here has always been guided by OAG but that's also because of the long focal length.

Olly

[PARTY MARTY]

Thanks Olly! That's what I do on the main mirror, When I finished with collimation I never over tighten the lock bolts too tight at the main mirror, I tighten the bolts just only nipped up slightly by hand. The main mirror is stablised with temperature controlled heater at the main mirror and the secondary mirror which prevents dewing up. Which had become a big problem in my dark site about 3 months ago now finally sorted!

[pringlepowell]

Right, purchased the QHY5 and adapter for my 9x50 finder scope, so here's to clear nights and some long exposure photography. See if I can do better than my best attempt so far:

[PARTY MARTY]

Well done Pringlepowell! You can't go wrong with this kit, You will get some teething problems I can guarntee that but you'll soon sort them out once you get used to Autoguiding with a finderscope! Your last was not that bad at all, but the thing is with the orion nebula you have to get some exposures in varying times and stages, You'll need to aim for 30 secs of a few frames to get the 4 stars, if you don't do them and you do just 300 secs exposures instead you'll wont get the 4 stars in the middle of the nebula! Good system worked for me at doing 25 x300secs, 15 x 120secs, 15x 60secs, 10x 30secs and then do 10-15 darks at 300 secs to elimnate noise! Everyone might have different approach than me! So go with a plan on what you're going to do and what you wanting to achieve! You already have got a good start in autoguiding, When I first started out I was doing 2 mins exposures, but as times gets better and the more practice you do with your imaging (making sure polar alignment is properl adjusted etc), you'll get better at this and you'll start achieving 5mins or even 10 minutes exposures like I'm doing now! You just need to keep practicing buddy you'll get there mate!