SH2-240 an ambitious failure

[lensman57]

Hi,

Nearly three months of inactivity due to the lousy weather and tonight I went for one of the most difficult targets in the sky, the super faint Simeis 147 / SH2_240.

The planned 4 hours exposure run was cut down after an hour due to intermittent clouds and by the time the sky was crystal clear again the target was now behind the trees at the back of the garden. So a pathetic one hour of data is all that I had after waiting since last Nov but anything is better than noting so please forgive the lousy image.

Atik 314L+, Sigma 70mm Apo Macro EXDG @ F2.8, Baader 7nm Ha filter on HEQ5.

4 X 900s subs with 51 Flats and Bias. Stacked and processed in PI. 

Thanks for looking.

A.G

[wxsatuser]

The start of a long drawnout relationship, no doubt.

How do you find the Sigma, see your using it at f/2.8, what are the stars like?

[lensman57]

The start of a long drawnout relationship, no doubt.

How do you find the Sigma, see your using it at f/2.8, what are the stars like?

Thanks, I wonder if this target is ever going to work for me giving the imaging limitations of my location, such a shame as the night stayed clear but top of the trees saw me off. The Sigma is great as far as the optics are concerned but mechanically leaves a lot to be desired. I have not noticed much CA if any but focusing with this lens is a hit or miss affair as the manual focusing mechanics are really at the bottom of the league.

A.G

[frostynixon]

Hello,

doesn`t look to bad! Keep on gathering data

br

[iksose7]

Hi AG, looks like there is plenty of signal but you may have gone a bit hard on the noise reduction without masking the stars and neb properly. Although i can understand that with one hour of data you may of had to stretch it quite a bit. I wouldnt give up on gathering data though, if you can hit 10 hours of exposure i bet you would have great signal to play with!

As for focusing, you may want to look into the TS Microfocusers, i have one for my EF200L, makes focusing easy!

Callum

[wxsatuser]

Thanks, I wonder if this target is ever going to work for me giving the imaging limitations of my location, such a shame as the night stayed clear but top of the trees saw me off. The Sigma is great as far as the optics are concerned but mechanically leaves a lot to be desired. I have not noticed much CA if any but focusing with this lens is a hit or miss affair as the manual focusing mechanics are really at the bottom of the league.

A.G

Was thinking of one, if a good one appears.

Good on you for trying this target.......if you don't try you never know.

[sloz1664]

Hi AG

I use a set of these to get focus with my camera lens:-

http://www.teleskop-express.de/shop/product_info.php/info/p3285_Microfocuser-and-focus-lock-fuer-camera-lenses-up-to-D-75mm.html

Steve

[lensman57]

Hi AG, looks like there is plenty of signal but you may have gone a bit hard on the noise reduction without masking the stars and neb properly. Although i can understand that with one hour of data you may of had to stretch it quite a bit. I wouldnt give up on gathering data though, if you can hit 10 hours of exposure i bet you would have great signal to play with!

As for focusing, you may want to look into the TS Microfocusers, i have one for my EF200L, makes focusing easy!

Callum

Hi Callum, totally agree with you. Needs a restack and a reprocess but TBH I think the only solution is more data but with more clouds and rain forecast for the rest of the week that is doubtful.

Regrads,

A.G

[lensman57]

Hi AG

I use a set of these to get focus with my camera lens:-

http://www.teleskop-express.de/shop/product_info.php/info/p3285_Microfocuser-and-focus-lock-fuer-camera-lenses-up-to-D-75mm.html

Steve

Thanks Steve, I will have a look at them. it looks interesting.

A.G

[lensman57]

I am not going to open another thread but here is a restack and reprocess in PI. Hope you find it an improvement. Still very noisy and the compression applied here on SGL does not do it any favours either.

Regards,

A.G

[iksose7]

Already looking better A.G, stars arent as crunchy and you have revealed a lot more of the nebula.

Callum

[martin_h]

Thats better!!! as always tho more data is the key with this object.

[PeterW]

Shows te brighter bits that the big dob crowd can aim to eyeball. Keep on getting data and you should get a good image.

Peter

[toxic]

Thanks, I wonder if this target is ever going to work for me giving the imaging limitations of my location, such a shame as the night stayed clear but top of the trees saw me off. The Sigma is great as far as the optics are concerned but mechanically leaves a lot to be desired. I have not noticed much CA if any but focusing with this lens is a hit or miss affair as the manual focusing mechanics are really at the bottom of the league.

A.G

you did way better that me i tried that target last night i got 1 sub 1200 sec HA and it shows nothing but stars at least you show some nebulosity well done.

[lensman57]

you did way better that me i tried that target last night i got 1 sub 1200 sec HA and it shows nothing but stars at least you show some nebulosity well done.

Thanks Chris,

This is the resulting stack stretched in PI with Histogram Transformation  with the STF parameters applied. I had a shock when I saw nothing. This target is really faint perhaps requiring many hours of data just to show the main body let alone the filamentary structure. Perhaps with  6 hour run @ f2.8 something will show.

Regards,

A.G