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Old 09-07-2012, 01:02 PM
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ZeroID (Brent)
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Cold Observations 8/7/2012

We have a run of clear night weather predicted for this week, hopefully right through to the next weekend. It started Friday night and Saturday night both of which I was unable to take advantage of but I got out Sunday night from about 7:45pm till 11: 20pm.

Sunday 8/7 Temp about 2*, no wind after evening katabatics died down. Seeing and transparency excellent for a suburban location. CBD LP apparent but less than usual due to the clear air.

Objective was to refine my alignment and get more pix, longer exposure, more frames. Also I picked up an older white USB PC keyboard to see if it was any better to use in the dim red light in the Ob than my black keyboard, Verdict --Definitely !!

Tried to do a 2 star alignment and seemed to be ok but had a lot of drift when I tried to stay on target. Strange when it was so good last time I used the system. gave up til later when there would be a better choice of stars to use.
Swung round to Saturn, NW sky. Drift still a problem although the GoTo got within a few degrees of target. Very stable air and I got down to a 4mm plossl before it became to hard to keep stable ( 312x ). The TMB 6mm (208x) & 9mm (138x) were best and I think I've proved my GSO 2x Barlow is a dud. Every time I've used it on any EP it all turns to crud.
Able to see the rings and the planet\ring seperation clearly but not able to discern any bands or other features. Managed to spot Titan but no other moons confirmed. Biggest and best I've seen Saturn.

Swung back up as Shaula\M7 region was clearing the trees on my eastern side up at about 80*. Mounted the DSLR on the accessory bar with a lens set at 55mm, f5.6, ISO 800 at 20 seconds for some widefield. Started squeezing off frames while manually correcting for the drift while I tried to determine in which direction it was all going wrong. Squeezed off about 140 frames of which I've got about 2 groups of about 40 that are usable. ( I am actually quite pleased with one group of only 9 frames to be posted a bit later ).

I still can't quite figure out where my alignment has gone all askew. My problem is partly not having an east or west horizon of any significance, just this slice of north to south sky which limits target selection during alignment. I am going to take SK II off the mount and put the 80 mm and a camera on bar with an upright corrector. Maybe then it might start to make sense a bit and it will give me more room to move while adjusting things. It just puzzles me that a week ago the drift was minimal and last night it was quite apparent.

Nonetheless it was a good night and again the advantage of having the Ob is just amazing. I think I would have given up astronomy if I'd had to setup and get this frustrated every time. I stiil enjoyed waving the binoculars around while the camera ran.
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Old 10-07-2012, 09:07 PM
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Paddy (Patrick)
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Can't help you with aligning Brent - the thought of mucking around with go-to and cameras is one reason I stick with star hopping visual observing. Glad to hear that you still managed to have an enjoyable night. Not looking good for observing here any time soon.
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Old 11-07-2012, 04:20 PM
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Lismore Bloke (Paul)
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Hi Brent,

The alignment issue is discussed here (problem could be partly polar alignment?):

http://www.iceinspace.com.au/forum/s...ad.php?t=24957

A good guide here also:
www.myastroshop.com.au/guides/synscan-align.pdf

I don't have an EQ6 but star alignment on the Argo I have can't be all that different. I just ensure that the stars are widely separated and not too close to the zenith. The accuracy falls off if the stars are too close together. The PDF above mentions doing 2 stars before the meridian and a third one after it. Apologies if I am mentioning things you already know. Clear skies. Paul.
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Old 12-07-2012, 06:26 PM
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Rex
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Can't help with ur problem Brent, but glad u managed to get some shots. I'm still waiting for the clouds to clear
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Old 13-07-2012, 05:53 AM
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silv (Annette)
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Perhaps you saw my 2 recent threads ?
Following them, I continuously improved the tracking of my mount (non-permanent, in our drive way. )

You have your observatory - but which items DID you move between your last session which ran well and this one which didn't run as smoothly as expected?

Assuming that you "know" all the theory around aligning, how well balanced is the gear each time? How well leveled is the mount? How spot on is the latitude set in your mount head?

My tracking improvement at my next session will go around balancing.
I'll tell you why:
I can see Canopus in the early evening and the mount doesn't have to slew far from park position. With Canopus I adjust my SCP alignment - moving the tripod so that it resolves the east-west slewing error of the controller. (I also used it for correcting my latitude angle but that seems to be really okay, by now.) After correcting for SCP and turning on the controller again, Canopus is (almost) spot on as 1st alignment star.

From there, I choose Antares as 2nd alignment star which is quite a bit of slewing. If all goes reasonably well here, my 3rd star is Arcturus in the north.
And here, my mount gets into trouble. I think I have noticed that the aiming is much better if I have balanced my scope better.
Makes sense to me, given the fact that from Canopus to Arcturus there is a lot of mechanical movement involved.
Possibly, I can also improve the 3 star alignment by choosing stars that do not involve a 180* rotation of the axis.
But I'd rather improve it overall - so I will work on my balancing next time we have good weather in Auckland.

I am of course only a beginner.
I think you might also benefit from doubting everything you configured, so far. Just like I did.

Edit: re-read your post and found the possible culprit:
Quote:
Mounted the DSLR on the accessory bar
Try doing your initial balancing with ALL the gear mounted that you will be using during your session. Including the eye piece. Amazing how leaving out the eye piece (or the camera battery) changes the balance - let alone a whole camera.

Last edited by silv; 13-07-2012 at 06:05 AM.
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Old 13-07-2012, 05:55 AM
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silv (Annette)
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But most of all, I just enjoyed reading your report.

Glad you got some nice exposures in, too!
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Old 13-07-2012, 12:07 PM
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ZeroID (Brent)
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Hi Folks, I think I made a wee booboo. I had a pretty good alignment a week or two back but when I went to use the system again it seemed off. BUT !! .. in between I had done some lunar work, with it's different tracking rate .. and I forgot to reset. You see where this is going ?

Note to self: Another step in the check list, CHECK TRACKING before you try to 'fix' things.

Having corrected that and now not trying to align to compensate for the difference I am heading back towards accuracy. I'll get it back to where it should be soon and going to give EQAlign and\or Alignmaster a go as well. It will push me to get the guiding system working.

Hey, it's all part of the learning curve and boy am I learning heaps !!!

P.S.
Silva > Mount is well balanced even after adding the camera. I have sufficient weight and the whole OTA with accessories will just hang almost in any position. Minimal pressure bias to contend with.
Whereabouts in Auckland are you ? I'm on the south side slope of Mt Albert

Last edited by ZeroID; 13-07-2012 at 12:22 PM. Reason: Added some stuff ..
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Old 13-07-2012, 02:12 PM
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silv (Annette)
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glad to hear! that checklist grows like tomato stalks.

wow, such a good balance.... I don't have that. But I'll figure it out, somehow. In RA, my Newtonian falls to where the focuser, finder and red dot finder are mounted. Hm, maybe, I can exchange finder scope and red dot finder position... and take off the red dot thingy. yup, that should give me a little improvement. Do you have an SCT? I reckon that is a bit less hairy?
If you have any idea how to better balance a newt especially in R.A.(the upper axis is RA?): much appreciated.

I am on the North Shore, between Albany and Riverhead. The glow from CBD in the east is quite prominent, even up here. I wonder how you can manage in Mt Albert. Our drive way is in a little valley of forested hills so my visibility horizon is higher all around. Could be better - not complaining, though.
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Old 16-07-2012, 10:52 AM
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ZeroID (Brent)
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Home built Serrurier Truss, very light OTA 'frame' (11kg) which requires no added weight at the scope end to balance it. I can slide the dovetail if required for OTA balance. Total weight up with accessories is about 17-18 kg which is well within the mounts capabilty.

I'm lucky in that being up on the south side slope of Mt Albert it just gets me above the city fug enough especially on nights where it blows the clear cold southerlies. I have good SCP visibilty and protected by a ridge and high treees to the east, my CBD direction. I get very good Sth to Sth West views but I keep my aim high for photo work. Only shoot when it goes above 90* of the SCP and that is marginal.

I've looked at property up around Coatesville way but doesn't suit the rest of our lifestyle. I'm not complaining about our position either. I get enough clearish nights to keep me going even fighting the LP.
Up on a ridge up north, have you tried to spot Andromeda ? 13" above horizon but it should be just visible on a clear night. One of my ambitions in life to see that big sucker.
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