TenChain Hill Resumes` - Page 3

lazjen (Chris) · #41 03-05-2014, 09:04 PM

Quite a temp drop, but definitely a good night in Brisbane.

pmrid (Peter) · #42 04-05-2014, 03:23 AM

What a cold clear night. Wow. That sneaked up on us didn't it?
The trouble with having so few decent nights is - apart from the obvious - that you don't get the time/opportunity to work out those bugs in your optical system that depend on it.
I'm trying to get this RC8 I picked up collimated and it's proving to be very elusive- even with a Tak collimating Scope.
Does anyone in this group have any experience with collimating an RC?

Peter

ozstronomer (Geoff) · #43 04-05-2014, 03:36 AM

Sorry Peter, I can't help but I expect Rick will Have a few Ideas on collimation.

Skies have been looking great all night, on to second target so I hope it holds till dawn

Geoff

RickS (Rick) · #44 04-05-2014, 08:28 AM

G'day Peter,

I have collimated my RC10 on a few occasions. I used a Tak collimation scope to get it about right and Al's Collimation Aid to get the rest of the way with a real star. I only ever adjusted the secondary and didn't ever need to adjust the primary (saw you asking questions about the primary screws the other day). If there's anything I can do to help let me know.

Seeing wasn't that great last night but I did get another 9 hours of data and we takes what we can get

Cheers,
Rick.

pmrid (Peter) · #45 04-05-2014, 10:21 AM

Quote:

Originally Posted by RickS

. If there's anything I can do to help let me know.

Thanks Rick. Using the Tak Col Scope, it seems to me that the primary and secondary are both bank-on. A defocused star brings some secondary adjustments but nothing gross. Problem is that there seems to be serious tilt remaining and so it seems now it becomes a process of elimination. There is a slight Y-Axis droop in the CCD-to-focuser connection. It's a slide-in no a screw-in job. The focuser is a FeatherTouch so I'm not looking there yet. Having said that though I did notice one of the 3 grub screws in the flange is missing.
I finally did a Bahtinov mask test last night - focus accurately in the centre then move the star to the 4 corners to check focus AND then, rotate the mask 90 degrees in each corner to see if there is an X-Axis shift. In fact I'm guessing it is a bit of each. And there was - pronounced on the left side and mostly on the top.

I adjusted a little for that X-Shift and it seemed that on the Bahtinovs at least I had eliminated it. But a 10 minute sub later showed I was wrong about that. So I'm back on a tilt but somewhere else. The last candidate is in the CCD sensor. It's an Apogee Alta U8300 and OUGHT to be right. Trouble is that there's no adjustments in those cameras. I may have to see if I can get hold of a tilt-plate from somewhere. I Think Teleskop Xpress in Germany sell one for the RC10.

Peter

allan gould · #46 04-05-2014, 11:09 AM

Peter
I have a 10" GSO RC and used Al's collimation aid to get stars sorted out ie to be totally circular in the frame. I then use SGP to do my focusing for me as I have found this is the only way to make sure I'm in the CFZ for my scopes. I have found that reliance totally on a Bahtinov mask can put stars on the edges out of the CFZ and get elongation. I also have a 10" SCT that I use Al's collimation aid to ensure that it's properly collimated. Don't have a Tak collimation scope as my RC was almost bang on when I got it and it just needed very small secondary tweaks to get it right. It's held it's collimation for over 12 months now. The collimation screws were really tight from day one.
If you still have tilt I would recommend that you get the tilt adjuster from Bintel. I have one but have not needed to use it.
Allan

allan gould · #47 04-05-2014, 11:24 AM

Peter
The tilt adjuster for the 8" scope is different from the 10" in diameter.
Bintel has it here for the eight inch
http://www.bintel.com.au/Accessories...oductview.aspx
Hope this helps but Al's collimation aid is the best thing since sliced bread for collimation and takes all the guess work out of it when used on a star.
I have astigmatism in my eyes which makes it difficult to judge a clean circle. ACA takes care of that and I've never had a problem since.
Hope this helps.
Allan

pmrid (Peter) · #48 04-05-2014, 11:44 AM

Thanks for that Allan. I'll give Als routine a try tonight before I tweak any more.
cheers
Peter

RickS (Rick) · #49 04-05-2014, 11:55 AM

Peter,

I have one of Gerd Neumann's heavy duty camera tilt units if you ever need to borrow it. It requires a male A-P 2.7" thread on both sides, IIRC.

Cheers,
Rick.

pmrid (Peter) · #50 04-05-2014, 02:23 PM

Quote:

Originally Posted by RickS

Peter,

I have one of Gerd Neumann's heavy duty camera tilt units if you ever need to borrow it. It requires a male A-P 2.7" thread on both sides, IIRC.

Cheers,
Rick.

Thanks Rick. I've ordered one from Bintel. It's a PITA when these great nights come along so rarely and you can't use them to the full. I'll have to content myself with doing some widefields on the little BabyQ instead!!

Peter

Doogs38 (Alex) · #51 04-05-2014, 05:23 PM

It certainly was!! It was a steady but quick drop to 4°C at my place (Walloon); my 14" mirror couldn't dump it's heat at the same rate and didn't get below 8°C - time to mod the mirror box for some fans! Regardless, enjoyed a night outside looking at all sorts of interesting things ... I can only imagine how nice (& cold) it was at 10Chains Hill. Alex

Quote:

Originally Posted by lazjen

Quite a temp drop, but definitely a good night in Brisbane.

pmrid (Peter) · #52 04-05-2014, 09:12 PM

Tonight was supposed to be about the same but it's after 9 and still above 12C. And the seeing is not too flash. Maybe its the setting moon doing it - hope so. I'm doing widefields around M83 and it's a bit ordinary.
Peter

lazjen (Chris) · #53 04-05-2014, 09:47 PM

This: http://earth.nullschool.net/#current...28,-23.68,1601 might also show why the seeing is not great.

I'm taking the opportunity to get some darks as I have none for this temperature range.

RickS (Rick) · #54 04-05-2014, 09:52 PM

My guiding is better tonight than last night, but not fantastic. It was pretty good at the start of the evening but has deteriorated. Still, at least the skies aren't opaque for a change

Tandum (Robin) · #55 05-05-2014, 12:03 AM

I just snuk out for back yard piss and thought it looked pretty good.

Not a cloud in that sky.

Passed near 10 chain on the Italian Stalian today Pete. Did you here it

Of course not ... but my ears are still ringing

Got a buyer coming tomorrow

I'll have to wash it I suppose.

pmrid (Peter) · #56 05-05-2014, 02:41 AM

Quote:

Originally Posted by Tandum

I just snuk out for back yard piss and thought it looked pretty good.

Not a cloud in that sky.

Passed near 10 chain on the Italian Stalian today Pete. Did you here it

Of course not ... but my ears are still ringing

Got a buyer coming tomorrow

I'll have to wash it I suppose.

What's next. A big Honda Gold Wing with built-in Tv and en-suite?
Peter

Tandum (Robin) · #57 07-05-2014, 04:57 PM

Nope, a periodontist gets the lion share

Still got the big green Beemer.

pmrid (Peter) · #58 27-05-2014, 02:08 PM

Well guys, I hate being the perennial pessimist but the sky gods make it impossible to be otherwise. Skippy says the weekend will be heavily clouded. We have had 3 nights in a row here of beautiful skies but that's no consolation to those hanging out for the Saturday. I'll revisit this forecast on Thursday but if it doesn't improve, I'll call Saturday night off and go do something else - something you can do indoors like sulk.
Peter

pmrid (Peter) · #59 30-05-2014, 01:46 AM

Well, that's that! The clouds are back and Skippy agrees with the BOM. This new moon goes the same way as the past 6 or 7 - down the celestial gurgler.
I'm taking the dog and going fishing instead of sitting here sulking. Hope I fare a bit better with pilchards than I have with telescopes.

Peter

Octane (Humayun) · #60 30-05-2014, 07:38 AM

Bugger!

I'm out at Cainbable with the wife. Only have her 50D, 100mm macro and my Polarie. Was hoping for clear skies.

H