Jewel Box in HDR

[avandonk]

This was just a quick test for the Meade 10" SN.

Details Canon 5DH, Meade 10" SN, Baader MPCC,Hutech LPR filter.
Exposures all at 250 ISO, 3x( 15s, 30s, 1m , 2m ) Warm night about 26C. Stacked and aligned with Registar. EasyHDR used to generate and LDR image from this data.

Large image 1.5MB
http://members.optusnet.com.au/~avandonk1/jbox.jpg

I am going to try the Hutech focal reducer in place of the MPCC should give me less vignetting. Should also make the 10" SN a bit faster f3.5 at least.

Bert

[leon]

Bert that is a top image of the Jewel Box, as expected, however if I may be so bold it just hasn't the punch that the name suggests.

It is not your imaging that I question on this object, but mine as well, you have done a fine job.

I too shot this object some nights ago, and as I had never even seen it, I expected as the name suggested that it would be full of punch, so to speak.

Although I did it right, and the processing was OK, I was quite disappointed with the result, and put it down to the lack of experience on my part.

However viewing your image tonight, it still lacks that punch, as the name suggests.

Leon

[skwinty (Steve)]

Hi Bert
Certainly better than mine, however slight elongation of stars show tracking a bit off.
My constant battle is to get good polar alignment as I am unguided with my setup.

[avandonk]

The elongation in the top right corner is due to a mixture of vignetting field curvature and slight error in the collimation. Full frame is very difficult to get everything perfect to the corners especially with fast Newtonians.

Bert

[skwinty (Steve)]

Originally Posted by avandonk

The elongation in the top right corner is due to a mixture of vignetting field curvature and slight error in the collimation. Full frame is very difficult to get everything perfect to the corners especially with fast Newtonians.

Bert

Hi Bert
I was referring to the centre of the image.
With my f/5 Newtonian 1520mm focal length I use a Coma corrector which I find works a treat with outer field coma distortion.

[iceman (Mike)]

What focal length does the new SN give you, Bert?

Where did you get it from and how much was it (if you don't mind me asking)? I'm thinking of an 8" or 10" newt or SN as my next DSO imaging scope.

Did the 5D come to focus without modding the OTA?

Lovely image, but really needs some more exposures to reduce the noise in the background. Leon it is a very tough target to process!

[Garyh]

Looking good Bert! focus and tracking look good.
Don`t know if the focal reducer will go to good on the newt but.
Much more exposure needed but as you mention this is a quick test.

[avandonk]

Mike the focal length is 1018mm with MPCC as measured against a TAL200K image (FL 1790mm with FR/FF). This is close to 1016mm that the scope nominally is quoted and well within errors. The OTA was modded with an aluminium plate fitted under the focuser for extra rigidity. The focuser had also been upgraded to a 10:1 Crayford. The mirror cell had also been strengthened and better/more bolts added. The SN is designed by Meade for astrophotography so focus position is far enough out to obtain focus with a DSLR or astro cam.

I bought it from an IIS member from the for sale threads on IIS. I did not really need it but it was to good to pass up at $1k with MPCC and the intelligent mods. When Ken James gets the Snake Valley Observatory built will park it down there where the dark skies would make the 10" at F4 really usefull for dim objects. It really needs to be permanently mounted. The field is remarkably good for full frame and any vignetting still makes nearly the whole frame quite usable. There is little or no vignetting on a C size sensor and in fact the superimposed Tal image is just a bit smaller than the field of a C sized sensor. The vignetting is mainly caused by the MPCC which has a rear aperture of 40mm. The diagonal on a full frame is 43mm.

Below is a flat taken with the 5DH and two jpg's straight out of the camera superimposed with RegiStar to show difference in fields between the Tal and the 10" SN.

The HDR process will show from noise to the brightest object. The night was hot 26C.

Bert

[avandonk]

Here is what it can do with a dim nebula, Cats Paw NGC 6334 with a near full Moon.

A stack of 11x120sec at 1600 ISO with HA filter.

Bert