I have had mebership to the site for a couple of months but have yet to post as the forum is so intense with information.
Having said this, I have recently graduated from binoculars and purchased a Skywatcher 10" Dob. My EP's are Plossl multicoated 10 & 25 as a standard accessory.
Some great viewing of M42 but planets are a little small so possible Barlow purchase in the future.
I am in Brisbane and am a member of the South East Queensland Astronomical Society (SEQAS).
I am having problems, all of a sudden, with my spotter scope alignment. I say all of a sudden because after a bit of a fiddle with all the movable parts and such I simply cannot get alignment. I have included pictures of the setup as this is worth a thousand words.
I've probably been a bit stoopid but I feel everything is set in alignment as default (factory) and have not gone near any of the collimation settings.
Now when I align the scope with the spotter I cannot for the life of me get the object into the crosshairs. I have to have the adjusting screws out to the max to get it anywhere near the crosshairs.
I have the manual and followed it to a tee and no problems before the other night.
As you can see from the pics, the tightening screws are starting to 'bite' into the groove.
As a consequence, I have had to go easy and when bringing back inside I take all the pressure of the scope again.
I have moved the band outside of the scope mount and usually the results are very good but this is not right and I am obsessive about all parts working (I'm an IT guy).
Can one of my learned associates please provide some assistance to a noob that does not want to break anything. I am really frustrated because without this essentail piece of hardware I cannot 'look' at anything smaller than the moon. Have done the daytime procedure and had all the problems of 'fixing' an object through the scope on a dob mount. I am not very easily frustrated and doggedly determined when faced with a problem.
I would have thought that you should have a roughly equal gap all the way around the finders holder. That is where the finder tube fits through the holder with the 2 adjusting screws.
If it has not been bumped hard or dropped to bend something i'd say you've just over adjusted it.
Try backing the screws off to get it to sit roughly centre in the holder. Then line the scope up on a distant object (mast,tree on hill,or something) then adjust the finder in small increments.
I would have thought that you should have a roughly equal gap all the way around the finders holder. That is where the finder tube fits through the holder with the 2 adjusting screws.
If it has not been bumped hard or dropped to bend something i'd say you've just over adjusted it.
Try backing the screws off to get it to sit roughly centre in the holder. Then line the scope up on a distant object (mast,tree on hill,or something) then adjust the finder in small increments.
Hope this helps,
Cheers,
Duncan
Hi Duncan,
Thanks for your fast reply and advice. Unfortunately, to no avail. I have turned the adjusting screws so that the spotter sits 'straight' or 'centred' in the mount. I have then focused the scope (25mm) on a distant line of trees (approx 5 klicks from my house). When I thus look back into the spotter the selected profile seems to be way way off to the left (inverted). In order to even get within cooee of the selected scope image I have to adjust the tension screws out to the max and still I can't get it to within the crosshairs. I tried a bit at a time and in small increments but this just made the journey extremely slow. This is driving me crazy. Could it be colimation or perhaps the paraboidal mirror is out of alignment with the secondary-mirror bracket. I can pretty safely rule out damage to the spotter as it seems pretty much 90 deg square and I can't recall dropping or voilently bumping it. This is a doosy but I'm confident it is something really simple.
I can do more images if someone needs a little more info.
In any case I appreciate your comments Duncan and look forward to posting or threading to you again.
Have you done a collimation on the scope. It could be that the primary or secondary has been moved in transport.
Other than that mate there are a lot of members around Brissy and they have clubs etc. down there. Take the scope along to a meet and get some help first hand.
I hope you get it sorted out quickly.
Unfortunately only meetings at this stage. Everytime we have a viewing night its overcast and/or raining. You know the story, buy a scope if you want to end the drought .
Anyways, the images are pretty clear but I have nothing to compare them to at this stage so I guess apart from tweaking I will just have to wait till I can crack a club viewing night and get one of the veterans to sort me out. Boy do I feel like a noob.
Johnno you might be able to arrange a one on one meeting with one of the club members or one of the members from here, late arvo would be good as at least you have daylight to work with.
Cheers and as i said i hope you get it sorted quickly,
Duncan
I've just come inside and signed in. Thanks fellow stargazers for your advice.
I've been trying everything bar mucking with collimation. This includes taking the EP seating (the hardware that the eyepiece sits in-for want of a better description) out and refitting just in case I inadvertently loosened a screw and it went off kilter but no joy.
I removed the spotter scope mount and checked it and refitted thinking that maybe it was not tightened in their snugly or a bit of debris might have caused it to be sitting in there abnormally. Everythings OK
I untightened and retightened EP's and Spotter and re-focused-all nice and clear.
If I remove the rubber banding from its alotted slot and roll it up towards the top of the spotter scope and then align I have much more success but that little rubber ring should be in its natural home so I imagine this quick fix to be less than ideal (I'm a bit pedantic about these things ).
If I grab hold of the spotter and hold it so the crosshairs align with the desired image I can almost tighten the adjusting screws to get it where it needs to be but then once I loose my grip I'm back in Hell.
To Blue Skies,
Hi and thanks for your response. It just occured to me that maybe the footplate you are talking about is the mechanism that the EP directly fits into. If so, I have reseated it and it looks pretty snug. If not I may need you to tell a noob such as I what the footplate is .
To Astroron,
Hello to you. I live in Bracken Ridge (actually on Bracken Ridge) I have a reasonable view of the skies to the north and west and the milky way at or close to the zenith. So Mars Saturn and Orion are pretty visible most of the night. The East and South aren't great. The East suffers terribly from street light pollution and the West is marred by roof tops. Is Bracken Ridge near you ?
To Duncan,
There's a lady in the club who lives at Albany Creek (just down the road from me) and is one of the major club players but I haven't plucked up the courage to ask her, or anyone else for that matter, for a little home tuition. I am however built to travel and am willing to share my problem with anyone who may be able to help .
To all,
I'm sorry I couldn't respond within family hours but I got caught looking for a solution out the back of my house. It's spoiling my viewing as everytime I spot something I can't really 'spot it' even with a 25mm. As far as starhopping is concerned I am a virgin. The moon is fantastic but I'm going to have to get a filter or a welders mask because that big ball of cheese sure do get bright.
Hope to hear from you all and thanks for making me feel welcome
We have an astro night at Cambroon on the 10th next month, you are welcome to come along It is about one and three quarters of an hour from Brackenridge, I used to live there but now live in the country.
If you dont mind a drive I am willing to give you some instruction any time.
Check my website for instructions of how to get here.
Cheers
See image below for what I'm calling a 'footplate." The bit that holds onto the stem of the finderscope holder. If this is loose or has been knocked a bit it wont allow you to align the finder nicely with the screws, the screws should only be for fine adjustment. From the problems you're describing it sounds to me that you need to look at this first. It should be bolted on with two bolts. Fiddle with them as required.
I know that country pretty well. You have made a very positive sea change. I remember going through Cambroon to see some family that lived on Obi Obi Road the Mapelton side of Kenilworth several years ago. I know a lady who hails from Conondale. I come from Condamine originally so I can appreciate the value of our dwindling dark skies. These are great dark skies!!
I would like to go on the 10th so hope to meet you there. It's on a Saturday so get there around 4:30pm (later or earlier??)
Cheers
To Blue Skies,
I think we may be getting somewhere. I just moved the footplate by hand and this seems to indicate where things are going wrong. You are beautiful, do you know that?
It obviously needs tightening but I have these terrible images of dropping a spanner onto the mirror. If I put some clean cloth over the mirror to dampen a possible butter finger moment this shouldn't affect the polish or the finish on the mirror should it? Im betting London to a brick that this is the source of the problem as up/down fine tuning is not the issue it is most definitely side to side adjustment. I should have clarified this earlier.
I would like to go on the 10th so hope to meet you there. It's on a Saturday so get there around 4:30pm (later or earlier??)
People start arriving after three o clock as it gives you time to set up and have a chat and and BBQ before it gets dark.
You can camp or if the spare bedroom is vacant, or even a mattress on the floor.
Bring warm clothes and warm footware a beanie and a chair, and of course your scope and Binoculars
It obviously needs tightening but I have these terrible images of dropping a spanner onto the mirror. If I put some clean cloth over the mirror to dampen a possible butter finger moment this shouldn't affect the polish or the finish on the mirror should it? Im betting London to a brick that this is the source of the problem as up/down fine tuning is not the issue it is most definitely side to side adjustment. I should have clarified this earlier.
Easy, just keep it level, then if you drop a tool it should just hit the metal tube on the opposite side of the finder and not glass. Little dents in the tube are cosmetic, they don't affect the performance of the scope. To foolproof it take the tube off the mount and put it on a chair or table, perhaps on a folded towel or blanket to stop it rolling. Perhaps looking out a window so you can see something in the distance to help you get it aligned right. Or outside, where ever you've got enough distance. Do it during the day, that should also make it easier to see what you're doing. Point at the top of a tree or lightpole or building as a guide. Then at night time find something really bright and fine tune it. Robert should be your uncle after that.
Anyway, hope you do get together with Ron in the near future. I had the pleasure of sharing an observing night with him in December when he was on this side of the country and he's a top gent.
Anyway, hope you do get together with Ron in the near future. I had the pleasure of sharing an observing night with him in December when he was on this side of the country and he's a top gent.
Thanks Jacquie, I enjoyed my observing session with you good people
How is the dome coming along
Regards to all
Easy, just keep it level, then if you drop a tool it should just hit the metal tube on the opposite side of the finder and not glass. Little dents in the tube are cosmetic, they don't affect the performance of the scope. To foolproof it take the tube off the mount and put it on a chair or table, perhaps on a folded towel or blanket to stop it rolling. Perhaps looking out a window so you can see something in the distance to help you get it aligned right. Or outside, where ever you've got enough distance. Do it during the day, that should also make it easier to see what you're doing. Point at the top of a tree or lightpole or building as a guide. Then at night time find something really bright and fine tune it. Robert should be your uncle after that.
Thankyou Blue Skies,
This has fixed the problem . No cracked mirrors, no messing with collimation. I scoped the object and adjusted the footplate as per instruction. I fine tuned the tension screws on the spotter and actually found myself unwinding them a bit.
The result is a crosshaired vision of beauty . I'll take it out tonight and fine tune it.
Don't know if you've followed my 'saga' but Blue Skies sorted me. It was to do with the footplate and its positioning. If I am being honest, a few nights ago I was out viewing and a sudden shower caused me to grab everything and trundle holus bolus to shelter. I am thinking in my urgency that i have shouldered the spotter mount and it has moved it that fraction. In any case the whole issue has gone away for now and I am spotting with pinpoint accuracy. Now I will have to learn collimation.
Of course all through my trial and error period the skies were clearer than they have been for some time and now that I am ready to star gaze its cloudy and rainy again. The guys at the scope shop didn't mention it would be like this !!
Im interested in your kit from your photo. Your mount seems nice and tall so that a stool and any adjusting that you do are back friendly. I have been using my scope long enough to realise I am going to have to modify my Dob mount at some point in the workshop.
Have you always had the 12"?? Have you used a 10" before, or still, as part of a collection?? Mines an F5 and the M42 looks beautiful using 25mm. I guess an extra 2" gives greater resolve at high magnification, especially the clusters.
As I have said, the 25mm and the 10mm give great images but the planets are on the dissapointing side. They are small with llittle detail and although I wasn't expecting Hubble I thought I might be able to resolve them better. Incidentally, they came with the scope (Plossl multi-coated).
I was wondering about a good quality Barlow but have been warned by club members that you can easily get a bad one if you are not extremely carefull. I also have a 2" adapter for wider EP's. I thought about going down to a 4 or 5mm when I get some spare dosh but for the moment I am updating my sky knowledge with charts and Stellarium. I'm just wondering if your 12" gives you closer images of DSO with greater resolve or is it more to do with magnification? Feel free to give some feedback when you get a chance (no rush)
Anyway thanks for your help and hope Weipa is fining up for your work. I am looking forward to going to Astrorons little star do on the 10th April (out near Kenilworth). Dark skies and hopefully zero dark clouds.
I knew signing up to this sight was a very crucial step in the right direction .
Thanks for your replies and i'm glad you got the finder issue sorted.
As far as the difference between a 10" & 12" Dob goes about all that changes is DSO's look a bit brighter. Nothing looks any bigger as such.
As for Planets a good Barlow will definately help, but the downside is the object you are looking at will be harder to keep in the field of view.
I haven't used my 12" Dob for months as i haven't been home. Arrived home last night to Atherton just sth/west of Cairns and it's raining anyway. Looks like it will be like this the whole time i'm home as well.
The other half is happy to see me so i better not complain.
The 6" Refractor and HEQ5Pro live in Weipa for the time being.
Haven't had much luck viewing up there either. Just have to be patient and wait for the wet season to end.
Cheers and happy viewing,
Duncan
Johnno
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).
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. I'll take it out tonight and fine tune it. 
All very sad. 
!!
. Looks like it will be like this the whole time i'm home as well.
