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guidescope advice please


Guest sharpie78
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Guest sharpie78

Hi guys, been a while since I've been on here cos i've been building my roll off roof obsy. hope everyone is ok :)


 


pier concrete was poured today so should be getting it all up and running in the next couple of weeks.....anyway, back to topic......


 


I've been using a 50mm finderguider up until now but I have a little bit (I stress a little bit) of extra cash so I'm looking to get a better scope for guiding.


I'm leaning towards an ST80 but I've seen a celestron travelscope 70 for a decent price and I aint sure which way to go. I'm trying to keep the cost down cos the obsy has all but cleared me out and xmas is just round the corner. 


any advice would be greatly appreciated as always  :) 


Cheers


Jack


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hi Jack.


you can`t say you been building a roll of obsy and not put some pics of the build on the forum, we would love to see them, L.O.L.


back to topis, i used a st80 as a guide scope and they are very easy to use and very effective, i piggy backed it on my gt81 and it worked very well, i also tried it with a dual mount bar and apart from the balancing issues it worked very well also, balancing while piggy backing was alot easier to do.


i then started to look at lightening the load so i got rid of the st80 and dual mount bar and bought a altair astro 10 x 60 guide scope, these are a lot lighter but a little trickier to focus than a st80 but you really need to only focus it once so once done you never need to do it again, this little guide scope fits lovely in the tube rings of the gt81 and has made the rig a lot lighter and easier to handle if i strip it down to take to meets and star partys.


i also found this tutorial very helpful, especially the part relating to the matching pixel scales of the guider and imager.


 


http://stargazerslounge.com/topic/188777-phd-guiding-basic-use-and-troubleshooting/

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Guest sharpie78

Hi Rob,

There is another element to my wanting to go down the ST80/travelmaster 70 route.....

I'm hoping to use the guidescope for video astronomy too, hence why I wanted to have a slightly larger aperture than a 50mm finderguider. I'm guiding using a cctv camera and metaguide for the guiding software, it's given me good results so far.

My kids are starting to get into astronomy now and there are several parents and teachers at their school who've expressed interest. I even got asked to go into my 5 year olds class the other day and talk to them about it all.

I figured that if they were to see the usual grey fuzzy blobs we get when looking at DSO's through an eyepiece they might lose interest quite quickly. The cctv camera I have stacks images internally and produces colour images with reasonable resolution (for a lay person anyway). If I can do video astronomy with the kids etc and use the same setup for guiding......it's a win win I reckon.

It's good to know an ST80 will do the job of guiding well, pretty sure I can't afford anything from altair at the moment. I know adding a different guidescope is gonna add weight to my setup but if I take off the finderguider the weight difference ends up only being 850g extra (ish). I'm figuring that with my HEQ5 being pier mounted and if I balance it really well, my weight issues shouldn't be too bad. 12KG is only 1KG over reccomended imaging payload total after all. (wouldn't be an issue at all if I got a beefier mount or the carbon fibre version of my quattro, one step at a time though. lol)

I'm gonna do a post of my obs build at some point. Annoyingly though, I've lost some of the pics of the middle of the build but I'm pretty sure I can get across the general gist of the progress from the pics I've still got. Watch this space :)

just back to the guidescope question briefly.....can I assume more aperture = better results for guiding ? I'm also assuming short f/l is better due to it having intrinsically lower weight ?

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Hi Jack, personally I would keep the finder/guider and upgrade your guiding camera. I use a 50mm finder/guider scope and a QHY5 camera with excellent results and minimum weight.]


Cheers


Ron


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Look forward to the build pictures,

Guide scope, if your going to use the scope for video capture as well then you'll be able to focus the st 80 better and easier, it also has a low focal length of 400mm, aperature doesn't really come in to regarding guiding, as long as you can focus on a star you'll be able to guide, a nice guide camera with a 1/3rd to 1/2 inch CMOs chip will be good ,the bigger the chip the more sky you can see so therefore more stars to choose from.

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Guest sharpie78

I know what you're saying about the weight Ron. The finderguider has given me good results (10 min subs with no star trail whatsoever) and is lightweight and would be even lighter with a smaller camera.


 


The cctv camera attached to it is a samsung scb2000 and works well.


 


I'm still trying to do things on a budget after the obsy wiping out my finances so the cheaper option is to get a better scope and carry on using the cctv camera for the time being. If I go for the better scope I'll also be able to do the video astronomy better with the kids etc. I am definately not ruling out a QHY5 or similar at a later date though. £60 for 2nd hand scope or £110 for 2nd hand QHY5 right now ? the scope wins. lol


 


When it comes to the aperture etc Rob......the chip is a 1/3" CCD, so when coupled with the 50mm finder I get a pretty good amount of sky to find a star in (haven't had any problems so far anyway). I think I'm mainly going for bigger aperture for the video astronomy really but it is good to be reasured it'll do the guiding job well too.


 


Thanks guys for confirming what I was pretty sure of anyway....It's always good to get a 2nd opinion from people who've already made these decisions themselves. :)


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Guest sharpie78

Well...I decided to bite the bullet and get an ST80. I got it for £55 (delivered) from ebay.


yes, I can hear the groans of people saying why did you get it off ebay ?


simple..........price.


cheapest on astrobuysell was £70 and a single dad with 3 kids and xmas just around the corner needs that extra £15 for stocking fillers :)


looking forward to testing it out


happy days :)


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Nothing wrong with ebay Jack if you get stuff at the right price, usually astro gear goes for silly prices on ebay so looks like you got a good deal.

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Guest sharpie78

I reckon I got a good deal too.


It's now piggy backed on my Quattro and guiding really nicely, all sitting atop my completed pier, in my 95% completed obsy. Happy days :)


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