Ha Horse Head

[richardo (Rich)]

Hi folks,
was out last night and the transparency was quite good considering conditions have been relatively poor in the past 2 months.
Short (for Ha) 1min unguided sub exposures. Tracking wasn't great this night... don't ask
Was quite surprised in the detail with the little reflection neb ngc2023.
Nothing great to the 'reef' area behind the Horse though.

Been trying to track down the extra '5th' spike in my imaging train.
Reblackened my secondary bevel & holder, flocked the focusing tube... still the '5th' spikes appears. I'm wondering if I need to blacken the bevel on my primary mirror, or could it be the corrector... the tube is very flat and so is the primary cell.... mmmmm Any ideas ?????

Any way here is a link to my front page if you like to take a peek, hit the thumb for more details
http://www.baytop-observatory.com

Hope you all had a great Xmas and happy new year to you all...
Here's to La Nino taking a hike and the weather settling to a good steady clear weather pattern for autum and winter

Cheers
Rich

[Ric]

Hi Rich, that is a nice Horsehead image you have captured, well resolved and detailed. Sorry, I cant help you with the fifth spike that's a bit out of my league.

Cheers

[Garyh]

Hi Rich,
Thats a fine horsehead, looks like the seeing was very good that night as well.... well done, Wish I could get that in 1min subs!!
I get a 5th spike as well in my newt, at the 45 degree spot and mine is caused by the focuser tube which sticks inside the OTA by about 2cms. When my MPCC turns up I hope that the extra back focus shall bring it out and hopefully no 5th spike..
Sometimes the mirror cell clips will do this too I have heard?
Cheers and happy new year!!
Gary

[h0ughy (David)]

wow that excellent, and looks like you got a satellite in it too

[Striker (Tony)]

Great image even with the 5th spike...I can see that would be annoying.

Still a very nice image Rich

Cant help you with the problem.

[atalas]

Very nice detail and contrast Rich !

[richardo (Rich)]

Thanks to Ric, Gary, Houghy, Tony and Louie, appreciated!!.

Houghy, that streak to the L/H side is actually refraction spikes from Alnitak.
Amazes me when I see this with other images with bright stars outside of the FOV that it actually picks it up.

Thanks for the tip there Gary. It could very well be my focuser as it protrudes within the tube about 10mm. It shouldn't affect the light path hitting the primary as such as there's 25mm either side of the mirror to the tube wall. Must be scattered star light hitting the brightish exterior of the fucuser tube..... I'll try flocking this as well, or might even try baffles before and after the focuser to see if this helps. Hopefully won't affect the warm current flow along the inner tube wall too much.
My mirror is a conical and as such doesn't use mirror clips, it's held to the cell via one large bolt that is resined into the centre.

Gary, the MPCC will need at least 55mm of spacing to your camera's ccd chips surface (plus the width of the MPCC). This will increase the distance away from your focal point, I think you'll probably find you'll need to rack inward to obtain focus. I could be wrong but I'm pretty sure.
Hope you get it sorted...

Cheers guys and HAPPY NEW YEAR !!!
Rich

[tornado33]

Great image there
I get a 5th spike on bright stars with my 10 inch Newtonian. Its caused by the off axis guider pick off prism and its light shield slightly protruding into the light path. Its presence varies from non existant to slightly noticable depending on the orientation of the off axis guider.
Scott

[acropolite (Phil)]

Nice image Rich, loads of detail and looks very realistic in B&W.

[richardo (Rich)]

Hey thanks Scott and Phil for taking a look and your comments!!

Yep still tracking down the 5th spike, not my focuser as it is well out of the way of the light path...... a friend has built a similar scope and has the same spike, but he has a totally different imaging train than me.... soooo I'm thinking it must be the bevel on the primary that's causing this diffraction.
I use a stand alone guide scope and ccd.

Geez, where's Mark Suchting when you need him... I know he'd have an idea if it was the mirror.
Any ways, I'm happy with the scopes performance, just need some decent weather to be able to put it to more use is all... I'm sure you guys will agree, the weather's been quite off!! Fires, extreme heat, cold and lots of dust and wind in between, not to mention clouds.

Ho hum, we wait......

Cheers for now
Rich

[spearo (Frank)]

Rich,
That is a very nice image of the Horsey indeed
I like the spikes!
very good stuff
well done
frank