Can anybody help?

discovery (Joel) · #1 17-09-2008, 10:09 AM

Hello I am currently paying off a 12 inch Dob from bintel and would like to know what I should expect and how does one learn collimation as I know Newtonians often require this kind of maintainance.

dannat (Daniel) · #2 17-09-2008, 10:23 AM

for collimation if you google andys shot glass there is an excellent tutorial - that gives visuals as well.
You could also use the search function on this site to look up the many old threads

discovery (Joel) · #3 17-09-2008, 07:19 PM

Thanks for your input I''ll certainly check out andys shot glass. It is a little daunting though.

erick (Eric) · #4 17-09-2008, 10:31 PM

Joel, you can expect to have a great time! Don't worry about collimation. You'll be able to easily get to a sufficient state for enjoyable viewing. Read up threads on this site and articles you'll find easily on the 'net and see what Andy has to say on his video, and you'll be right. Ask away, any questions, when you are ready!

discovery (Joel) · #5 18-09-2008, 12:05 AM

Thanks for your reply, I checked out andy's site it was great all my worries about collimation are gone, would be advisable to buy a collimation laser or eyepiece later on?

erick (Eric) · #6 18-09-2008, 12:51 AM

Joel, yes, you need a tool or two sometime. Again search for threads on this site. I suggest you search for "cheshire" and "laser collimator" - happy reading.

However, knowing what you are looking for now, ahving watched Andy at work, you can do a respectable job by eye alone. Your Bintel manual will have a reasonable section describing collimation. The one thing that will help is the el-cheapo "collimation cap". Pick up an empty 35mm film cannister. Throw the lid away. Drill a 1-2mm hole in the centre of the bottom. Fit this into your 2"--1.25" adapter - push it in from underneath, with canister bottom upwards, until the lip stops it going in further. Tighten up the compression ring. Pop into focusser. Look through hole. This keeps your eye position centred in the focusser while you make adjustments.

However, don't be surprised if the scope arrives from Bintel fairly well collimated.

rmcpb (Rob) · #7 18-09-2008, 08:21 AM

Joel,

If you have the money, just add a Cheshire eyepiece to your order. Money really well spent.

Above all else, enjoy your scope and don't get too hung up on collimation, it will get easier and better with practice.

discovery (Joel) · #8 18-09-2008, 10:29 AM

I checked out Bintels site and decided to get them to throw in a collimation tool heck I'll need it later.
Now I have another question about filters. I've already got an orion sky glow filter on the way and am thinking of getting some colour filters. Opinons?

erick (Eric) · #9 18-09-2008, 10:31 AM

Joel, search "filters" here. You'll get lots of hits, but there were several detailed threads giving references.

For coloured filters, the views appear to range from "waste of time" to "can be useful in certain circumstances".

discovery (Joel) · #10 18-09-2008, 10:38 AM

So all really trial and error. What really want to do is cut down the glare from the planets. Bintels is sending me a #ND 96 filter for the moon could this be used on other bright objects a.k.a planets?

erick (Eric) · #11 18-09-2008, 10:45 AM

Neutral Density filter - sometimes might use it on Jupiter or Venus when they are at their brightest, but usually not required. Different people react differently. Some have no problem with full Moon in a low power eyepiece (as you go to higher power, the image is fainter - you are seeing less of the object, hence less of the total light is entering the eye). Some find it hurts too much and really need a filter.

discovery (Joel) · #12 18-09-2008, 10:55 AM

I am getting the 12 inch dob as an upgrade from a celestron 90mm refractor. The views through the refractor were pretty good the moons of jupiter were resolved into tiny balls and I could see two very faint bands on the planet. The horsehead was just a faint blurr had to use averted vision to get any kind of clarity. What difference can I expect from the 12 inch Dob?

erick (Eric) · #13 18-09-2008, 11:16 AM

You saw the horsehead nebula in a 90mm refractor? That's pretty impressive. Perhaps you mean the nearby flame nebula?

People have different experiences, but my general understanding is that horsie is hard to catch in a 12" reflector. Need dark sky site and averted vision, and careful selection of eyepiece for correct exit pupil apparently helps. Not sure if any particular filter helps. This will be my first season of trying with my 12" - I'm looking forward to the challenge.

I expect that Jupiter will be spectacularly better (in good seeing conditions) - 12" reflector versus 90mm refractor.

discovery (Joel) · #14 18-09-2008, 11:27 AM

Which deep sky objects will appreciate the large aperture and 1520mm focal length of the dob?
As andy would put it
"I feel like an asronomical idiot"
(a fuzzy object in the eye piece somewhere near orion and a tad over excited and a total newbie may result in misidentification)

erick (Eric) · #15 18-09-2008, 12:04 PM

Quote:

Originally Posted by discovery

Which deep sky objects will appreciate the large aperture and 1520mm focal length of the dob?

OK, here is the list of those that won't benefit from the bigger aperture and higher resolution:-

Ummm? Errr? Cannot think of anything...........

That's about it. I'm sure everything will be better. Let's see what others say!

ps. By the way, if it is the Flame Nebula you saw, well that's not an easy target as well - not tough, but not easy

. The 12" aperture will help greatly but get to dark skies before you try.

pps. "Astronomical idiot" "mis-identified" "looking in the wrong place" - join the club

CoombellKid · #16 18-09-2008, 12:10 PM

Quote:

Originally Posted by erick

Not sure if any particular filter helps. This will be my first season of trying with my 12" - I'm looking forward to the challenge.

Try a HBeta which is used for the Horsehead.

regards,CS

discovery (Joel) · #17 18-09-2008, 06:12 PM

Patience is a vertue and you guys certainly have that.
Thanks again for answering my questions.

Anyways back to the waiting, for my dob that is.

rmcpb (Rob) · #18 19-09-2008, 01:52 PM

A late comment here. Sit on your hands as far as filters and other accessories are concerned. You have a brilliant scope with reasonable eyepieces and a collimating tool on the way. Get out under the stars and have lots of fun then after a while start to think how things could be improved.

After saying that, you do have a red torch, planisphere and stool don't you??