Night of Firsts

[NigelG]

Last Saturday night was one of my best nights this year.
The first time I have had dew heaters, normally my scopes are dew up by the time I done my alignment.
This was my first Bubble, and first 600 sec exposure. This is a single 600 sec HA exposure, taken with my Atik 314L+ through the Altair Astro 102. Just stretched and a little Gamma in Registax5.
Some of the stars are slightly elongated so I will have to give Drift Aligning another go.


https://www.dropbox.com/s/t5jlwihkmpzdkgh/NGC7635-001Ha.jpg


What I would like to Know is........

How did the Meerkat get hold of the crystal ball ???????

Nigel

New link added

[JohnP]

Some of the stars are slightly elongated so I will have to give Drift Aligning another go

Nigel - are you sure elongation is caused by polar misalignment - I spent many hours trying to do drift alignment because I thought it was the solution to the elongated stars I was seeing & in the end it was flexure. The only way I finally solved the problem was by moving to an Off Axis Guider...

Nice image - what was total exposure...?


John

[MarkS]

Good image Nigel - you ought to be pleased with that.

Tell us more about your setup - are you guiding or is this unguided.
The elongation is uniform across the whole image and appears to be in the Dec direction (not the R.A.)

I think you're mistaken about the Meerkat - it's a ferret!

Mark

[RobertM]

and there's a shark in the crystal ball !

That's a really good sub Nigel, you do have some north/south movement but otherwise it could probably do with slightly less exposure blowing that shark (those chips are so sensitive!).  the movement might be due to being a bit off in PA but also differential flexure between the guider and imager chips could cause that too.  Check that both guider and imager (via focuser) are rigidly attached to the telescope as well as verifying polar alignment.   A cure for differential flexure is the OAG route as John suggests - I think most imagers tend to go that route in the end especially for long focal length telescopes.

Robert

[NigelG]

Thank you for your comments.
My setup:- https://www.dropbox.com/s/eem7xq01dbnjrid/2012-09-15%2018.52.55.JPG

Imaging:- Altair Wave Series 102mm F7 Super ED Triplet APO, SharpSky focuser, Finger Lakes 8 x 1.25 USB filter wheel (L R G B Ha OIII SII Hb),Atik 314L+ mono
Guiding:- Sky Watcher EVOSTAR-80ED DS-PRO, SharpSky focuser, Atik Titan mono
Mount:- Observatory based NEQ6
Software:- Maxim and Registax

Nigel

[RobertM]

Nice setup.

From that picture I would think that any flexure is probably due to the ED80 part of the setup.  The focuser drawer tube is nearly fully extended and the power/USB cables are not best placed.  If it was me then I would wind the focuser most of the way in and use an extension to fit the Titan; also tape the cables to the scope to prevent cable drag.

Hope that helps
Robert