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OMG! Surely the worst horsehead & flame pic ever!

cloudbuster

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cloudbuster

cloudbuster

Posted
Posted

Not so much the horsehead, but more like a pig's ear! :):eek::D I'm really almost too embarrassed to post this pic here :( Ive only ever photographed the orion nebulas before, and thought I'd give the horsehead and flame nebulas a go the other evening. Here's how I did it:

Skywatcher equinox 66

Canon 300d

800 asa

16 subs 300 seconds

darks as above

20 bias 1/4000th sec

stacked in DSS

Processed in pixinsight

Please can someone tell me what went wrong? There is just a hint of the flame nebula...nothing more!

Any help greatly appreciated

cheers

bob :)

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cgarry

cgarry

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cheers Chris...any advice for me tho? the sky was darkish....and i chose similar exposures to other peoples, so what do you think went wrong?

cheers

bob

HI Bob,

I am really no DSO imaging expert, so I shall leave it to those who know what they are doing to advise you! I am sure they will soon have you producing spectacular images.

Cheers,

Chris

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Ben Ritchie

Ben Ritchie

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Hi Ben. no the camera is not modified.

I think the basic problem is not your technique, but that you've picked a rather difficult target for your equipment.

The horsehead is a 'dark nebula' of dust in front of an emission nebula that's ionized by sigma Orionis - so to 'see' the horsehead you've got to image the nebular emission, because the horsehead itself doesn't emit light. However, an unmodified DSLR is not very sensitive to the H-alpha line that's emitted by the ionized gas, so getting enough signal to 'see' the horsehead is very hard.

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AndyUK

AndyUK

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Hi Bob - I can see the glow from Bristol from where I live... :(

Having my camera modded enabled me to "see" a completely different view of the sky at night, but it did cost a fair whack (I wouldn't dream of doing it myself!).

Skywatcher 2" filters get a good write-up for the price though (less than £30 new) and you'd be surprised how much "cr*p" they cut out...

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AndyUK

AndyUK

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Hi Ben - I totally agree...

Getting the camera modded to capture the emission is also essential in order to capture such faint details / nebulae, but wouldn't you agree that whilst you may be able to pick up the "red" end of the spectrum with a modded camera, unless you can cut out as much of the "sodium streetlight" glow as possible, then the chip will pick that up first before it really has a chance to pick up the fainter emission signal...?

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lukebl

lukebl

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I'd say it's a combination of a tricky subject for an unmodded camera and lack of a light pollution filter. I use a Skywatcher LP filter and it really makes a difference.

However, I wouldn't be too hasty about going to the expense of getting the camera modified immediately. You can get really good results on most subjects without modding the camera. I was quite pleased with the results of my Rosette and Cone nebulas, which were taken with an unmodded camera.

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lukebl

lukebl

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Thanks guys. and Luke, those two samples of the cone & rosette nubulas are great! where can i get a skywatcher 2" LP filter, and how do i fit it to the camera....silly questions i know!

Thanks! I use a 2" LP filter fitted to my Coma Corrector. You can get them here

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Ben Ritchie

Ben Ritchie

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You can get really good results on most subjects without modding the camera.

Absolutely, just pick any broadband source (galaxies, open/globular clusters, reflection nebulae) rather than emission-line nebulae. Would be a very long time before you run out of targets given the weather in this country.

wouldn't you agree that whilst you may be able to pick up the "red" end of the spectrum with a modded camera, unless you can cut out as much of the "sodium streetlight" glow as possible, then the chip will pick that up first before it really has a chance to pick up the fainter emission signal...?

Yes, certainly.

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AndyUK

AndyUK

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Not a silly question at all... The answer is yes, but you're then capturing more of the data you want, and cutting out a lot of the data that you don't - You'll be exposing for the object and not the light pollution...

I suggest you give Steve @ FLO a call and discuss it with him - Not all light pollution is the same spectrum and when I bought mine he said that if it didn't work in my area, he'd happily give me a refund... However, I'd be pretty certain that much of yours is the good old orange sodium cr*p (as I can see it from where I live) so I'm pretty sure you'll see a significant difference and be able to stretch the images more...

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lukebl

lukebl

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one more silly question: wouldnt a light pollution filter effect the exposure times, in much the same way as a polarising filter does for conventional photography?

Yes, it does affect exposure times slightly, but the benefits far outweigh that disadvantage. The darkening of the background is quite striking when using the filter. Incidentally, the Skywatcher LP filter is the cheapest option. Other types of filter are available and, I believe, better than this one.

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