Ob Report, sort of ...

ZeroID (Brent) · #1 25-10-2010, 08:59 AM

Had some friends round for dinner Sat night and the weather has turned into summer so the 10" has been sitting up on the concrete wrapped in plastic for about 3 days now.
After dinner sky was reasonably clear ( I thought ) and Jupiter had popped up in the east so I got the little 4.5" out on the deck for a quick look and show. 20 mm wideview and then 2 x Barlow impressed very technically minded male friend who had already had a full mecahnical/optical rundown in the afternoon of the 10". Four moons and some banding visible.

So I got ambitious and carried the 10 " down to the deck Jupiter being not visible at that angle from the concrete pad. NOW male friend got very excited with the view. It was quite awesome although I'd noticed that although seeing was good, transparency was not great at all, about a 3 maybe. Still air but thin high mist. I moved the scope back to the pad and had a hunt round and managed to find and impress him with M7 after finding it with binocs. But transparency was down to about 1 by then so any further viewing was really pointless. Friend went away about 11pm very impessed and talking about maybe getting/building a scope. I shall cultivate this desire carefully.

After they had left my better half commented that she had yet to see Jupiter through the new beast so we went outside. Jupiter by now was almost at zenith and although transparency was not great it had improved so we found Jupiter and she was impresed with that. I must say that the 10" over the 4.5" is a massive optical improvement. It was also a full moon ( which wasn't helping viewing of course) and she suggested a quick look at the moon. I knew it would be bright and I haven't made a mask yet to fit but to put it bluntly I was blown away by the view. Yes it was bright but the clarity of the features was just outstanding !!! Far outranking what I now perceive to be quite a cheap 4.5" scope.

Definitely will make a mask and the moon will become a bit more of an object of interest especially as it will lend itself to photography better for now with the DSLR.

So killed several birds with one stone. Maybe converted a friend, got tacit approval from my wife to continue and found a new subject to try and capture better. Not the best observing night but certainly an excellent night for astronomy all round. Now just waiting for 2" crayford and some more EPs to arrive and I'll be into upgrade mode.

mental4astro (Alexander) · #2 25-10-2010, 09:13 AM

Hey, Zero, good luck with furthering the "conversion" of your mate,

.

I'd carefully consider makeing a mask for your scope to tone down bright objects. I used to think that a mask was also the way to go, not any more.

If you think about it, the reason for NOT masking is within your very post. You compared the images given by both scopes, and yourself say that the 10" killed the 4.5". Why? APETURE!

Masking will, yes, reduce brightness, but it will also kill the resolving power of the scope, which is what gave you such a good image.

I thought filters where, well, bull. Not any more. Filters will tone down the brightness, but the resolving power will STILL be there.

There is a thread on the better filters for this purpose in the 'Eyepieces and Filters' forum. I've made my arguement on my choice. Others offered their arguements too, good ones too. I'd suggest reading that thread and deciding which way to go:

http://www.iceinspace.com.au/forum/s...ad.php?t=66928

I've used my polarising filters to tone down the Moon when photographing the partial lunar eclipse earlier this year using my 5" scope and webcam (which I made following the instructions in the Projects and Articles section,

). Had too, damn thing was so bright. A mask would have killed the resolution of the pics.

Mental.

Paddy (Patrick) · #3 25-10-2010, 02:50 PM

Good to hear that you had such a good experience with your new scope. I'll second Alexander's comment about aperture and resolution. Moon filters are quite cheap and if one's not enough, you can piggy back them. If you do want to use a mask, from my miniscule understanding of the optics of resolution, you'd best go for a central obstruction rather than an annular one as your resolution comes from the width of you collecting surface.

Wait 'til you get to look at the moon when it's got a terminator - then you will really appreciate your bigger scope.

ZeroID (Brent) · #4 25-10-2010, 05:38 PM

Ok, ta guys for the info. Didn't realise that issue. Might try an annular mask just as an experiment, (cardboard is cheap !!) but when the new focusser gets here I'll start looking for filters.
I've seen terminator views and appreciate the difference. Think I'll be spending a bit of time on our satellite in future.

Suzy · #5 26-10-2010, 04:01 PM

Great story there Brent. Priority no.1 is to get your wife interested (as you did) so she will let you spend lots of money on astro things.

I just love peoples reactions when they see through a scope for the first time .. so priceless!

ZeroID (Brent) · #6 26-10-2010, 07:43 PM

Ta Suzy, she already has a very technical and scientific bent so it's not a hard job. She is impressed and proud ( tells everyone at work ) how I've built this 'monster' from almost junk in the garage.
It also helps that I can do reasonable viewing from just outside the lounge in the back yard. ( Also means a cup of hot choccie is quite nearby or something stronger should the need arise.)

And 2" focusser is on it's way now after a few false starts. So some more upgrading to do. Also picked up a 6mm and 25mm Plossl which will extend my selection a bit.

Right, gotta go, 47 Tuc is waiting ! Somewhere !