9x50 finderguider or st80 guidescope?

[Atreta]

guys i need another piece of  advice.

a friend of mine is in the usa and i need to get or a 9x50 finderscope(my telescope came with a 6x30) or an orion st80? it will be use with the 130pds.

the price difference is minimal and if the st80 is recommended what else is needed to use it as a guidescope?

thank you again.

[Dr_Ju_ju]

I use an ST80, & have added an Altair Astro diagonal and a QHY5L, job done...

[Atreta]

thanks, will it work good with the 130 pds and would any 1.25" diagonal work? the store i checked doesn't have the altair one you mentioned.

[Tinker1947]

I'm not sure i understand why you would want a diagonal, my ST-80 has a some extension tubes so there's next to no flexure with a CCD hanging out the end....It does have guide rings so the image in PHD has the DSO dead centre on the viewing screen this also matches the CCD Sensor so getting the DSO positioned is really easy, I also use this the Polar Align with the Handset before plugging EQMod in....

[Atreta]

thanks tinker,

i was taking a look at the stores and it seems like the st80 is just the ota, with the other accessories it will be way over the 9x50 finder.

i'll take all you guys say into consideration and will post what i decide.

[carastro]

Both the 9 x 50 finderscope or the ST80 will work.  I used both on my 200pds.  The finderguider is lighter.  You will need an extension piece (rather than a diagonal) for the ST80 in order to get focus.

Carole 

[Tinker1947]

I have used a 9 X 50 finder scope and it worked ok, there is a adapter screws in the EP end that has the right thread for a Lodestar ......you will need to check what Finder Scope and CCD adapter is required, this link is where i got mine from...

http://www.modernastronomy.com/shop/adapters/c-mount-adapter-for-straight-through-finders/

[Magnus_e]

I was using the 9x50 for guiding, when i was using my ST80 as a imaging scope.

Now i use the ST80 for guiding with improved results.

Instead of having a diagonal on the ST80 i use the 9x50 to visually find callibriation stars when setting up.

When i only had cameras and no eyepease i had big problems finding the correct callibration stars.

Using the ST80 for guiding and the 6x30 as a visual finderscope would work great, i think...

[Dave In Vermont]

You would do well to use the ST80 as it will accept standard 1.25" EP's. And one such EP could be one with a reticle - possibly an illuminated one with an adjustable brightness-dial.

I was recently looking to get a 8 or 9 X 50mm finder (for my ST80, no less ), and couldn't find anything I could outfit with such. They all had an all-in-one small diagonal I couldn't upgrade to a 1.25". And I wasn't going to shell out the extra £ for an illuminated RACI. I settled for a GSO 8 X 50mm RACI.

GSO makes a very nice 1.25" dielectric diagonal with compression-band. Optically, it's truly worth the price. That is if you don't want to go waaaay much more money.

With a totally tricked-out ST80 with a 2" William Optics diagonal,

Dave

[Uranium235]

Personally, I'd go for the 9x50 every time. Its lighter (hence gives less, or no flex), cheaper, easier to mount, and you never fail to find a guidestar.

The only caveat being that you cant use the normal finder bracket for it - you need some mini guidescope rings. However, the results speak for themselves:

Edit:

However, for a focal length of over 1000mm (10" newt, SCT or RC) - I would probably use a different solution.

[StevieO]

When I started guiding I bought an Orion Awesome package which included the ST80, Starshooter guider, rings, extension tube and dovetail bar. I worked really well, the drawbacks being that it was quite heavy, required focusing in the normal manner, and, once attached to a scope, was a faff to change to another scope.

I now use a 9x50 for all my guiding. I got a bracket from Modern Astronomy which joins the guide camera to the scope (make sure you get the right one - Celestron and Skywatcher finders are made in the same factory but can differ in the eyepiece thread). The scope and holder fit into a standard finder shoe, so can be swapped from scope to scope without difficulty, and focusing is a one-time operation. It's much lighter too. I get great guiding from this setup and would recommend it.

StevieO   

[lensman57]

guys i need another piece of  advice.

a friend of mine is in the usa and i need to get or a 9x50 finderscope(my telescope came with a 6x30) or an orion st80? it will be use with the 130pds.

the price difference is minimal and if the st80 is recommended what else is needed to use it as a guidescope?

thank you again.

You don't need the ST80 for guiding. The 50mm finder guider is more than good enough up to 1000 mm of FL and as an added bonus it is much lighter, it stands less tall so the balance does not get disturbed, has a much wider FOV so you pick out more guide stars and is about a whole F stop faster so you do not need super sensitive and expensive guide cameras. A few weeks ago I used my Canon 200 F2.8 with my 383L+ to image SH2 129 and these lot were mounted on top of my Ascension 80 Apo that served as the guide scope. I had a lot of trouble getting the balance right and the guiding at 480mm of FL was not easy to say the least. With the benefit of hindsight I should have used my 50 or 60mm guide scopes rather than the heavy 80mm .

A.G

[Snaxmuppet]

This is an interesting question and it seems that there is no right/wrong answers. Both seem to work well. It might depend on your target and if there is a bright enough guide star in the FOV. I bought an ST80 for guiding but when I found that I could use a standard 9x50 finder I switched to that. In fact, I haven't decided which is best as I haven't yet used either enough times yet but if the 9x50 works well then that would be my choice as it is lighter and easier to set up. I certainly find balancing easier with the finder.

[redfox1971]

So am I right in thinking for a long focal length scope say my cpc800 with focal reducer that brings it to f6.3 I would benefit more from the St 80 than the 9x50 guidescope which I already use as it is at the moment I always get a bit of star trailing would this improve with the st80 or make no difference?

[Tinker1947]

So am I right in thinking for a long focal length scope say my cpc800 with focal reducer that brings it to f6.3 I would benefit more from the St 80 than the 9x50 guidescope which I already use as it is at the moment I always get a bit of star trailing would this improve with the st80 or make no difference?

It could be a mixture of, Polar Alignment, Balance, The Mount, and the Guide Scope,  anyone can add star trails, or a mix of 2 being just a little bit out.....is the pub/brewery still working up the hill round to the right, its been a long time since i done all the pubs going down the hill....

[redfox1971]

Hello tinker 1947 my images always seem to be OK in the centre off the image but the further out to the edges always seem to trail towards the centre from each corner I have tried the recommend spaceing from ccd chip to focal reducer but doesn't make a lot of difference.yes the Three Tuns brewery still going strong got the Michaelmas fair back this year on the 19 September so should be a great day night of entertainment.

[Tinker1947]

Hello tinker 1947 my images always seem to be OK in the centre off the image but the further out to the edges always seem to trail towards the centre from each corner I have tried the recommend spaceing from ccd chip to focal reducer but doesn't make a lot of difference.yes the Three Tuns brewery still going strong got the Michaelmas fair back this year on the 19 September so should be a great day night of entertainment.

is that the field flattener/focal reducer f6.3, it sounds like a Newt Coma, so if its spacing FLO do a Baader Vari Focus adapter i its very precise with the adjustment, it people say its the spacing i would go for one of those....here's a link...

http://www.firstlightoptics.com/adapters/baader-varilock-29-lockable-t-2-extension-tube.html

http://www.firstlightoptics.com/adapters/baader-varilock-46-lockable-t-2-extension-tube.html

[Atreta]

thank you everyone for the answers, i decided  to go for the 9x50 finder because i got in hand the adapter to turn it into a guider and the st80 would give some more expenses like rings and dovetail to place it over the 130, and weight was also taken in consideration as you guys mentioned that the finder will be much lighter.

another doubt is if it will fit the original finder holder(don't know the right word for it).  Uranium mentioned that will be needed some rings to secure it, but can i use it in that holder till i get those rings?

[Uranium235]

It is possible to use the standard finder bracket (for now), but you will need to stiffen it up somewhat. I used to pack mine out with masking tape to take the slop out of it.

Also, you must remember to take any cable strain off the guide cam by using velcro straps or a bit of tape - but prefarably velcro becuase tape can leave a bit of muck on your telescope after a while.

Something like this is what you should be aiming for when you can afford:

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_20

I chose the Baader bracket becuase it all allen bolts apart, leaving you with a mini dovetail and rings.... obviously a bit more expensive! (but rock-solid)

http://www.firstlightoptics.com/finders/baader-mqr-iv-finder-holder.html

[Atreta]

thanks, Rob for the tips and the links.

i´ll try to set it up when it arrives. don't want to spend right now with rings because i'm saving for an LP filter later on.

[malc-c]

I use an ST80 with QHY5 on my 200P.  I've also tried the same camera on the finderscope and both work.  However, given the smaller field of view in the ST80, the tracking will be tighter if you get things right.  It's easier to get a really flat graph in PHD with a finder-guider than through an ST80 because of this.  However if this will be noticeable with the 130, and if the difference is that noticeable in the resulting images is subject to personal interpretation.  Any form of guiding will give good results.

[Atreta]

yes, i think it will be a big jump when i start with guiding, can't wait for the finder to arrive.

[carastro]

 can i use it in that holder till i get those rings?

I used the Finderscope bracket to start with, and it worked well for quite a long time.  So long as the finderscope is tight and not wobbling around it should be fine.  I did later on buy some small finder rings because I was getting some flexure, but still not really sure if that was the problem.  

Carole 

[Atreta]

thanks Carole, i didn't want to spend with something else for some time.

just got a bahtinov mask, guide camera and a CC, pockets are empty now

[Garethr]

Frank,

I use my 9x50 finder scope clamped in a couple of 2" pipe clips with rubber inserts, really solid with no flexure but you will need a dovetail or something to fix to on the main scope rings. There is a picture of my set up on a previous post somewhere I will try to find it.

Gareh.