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Old 18-01-2009, 05:28 PM
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Quark (Trevor)
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The Witches Head

Hi All,

Wondered if it is feasible to image The Witches Head with my 450D and a 17-85mm EFS at 85mm, mounted piggy back on my scope.

It is a massive object but is it expecting to much to do this at 85mm.

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Trevor
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Old 18-01-2009, 05:37 PM
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RB (Andrew)
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Trevor it will fit and will occupy around 1/5th of the frame (vert) if you place it centre.
You will need a lot of exposure though with the 17-85mm EFS.
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Old 18-01-2009, 05:48 PM
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Thanks Andrew,

Just wanting to ease into DSLR astro work and I was looking for piggyback targets to get the hang of taking flats, bias and darks for longer exposures.

Its all new for me and I was interested if I could expect to get this object with such a basic lens.

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Trevor
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Old 18-01-2009, 05:57 PM
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RB (Andrew)
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It's a very nice object indeed but it needs a lot of exposure.
I'm hoping to have a go myself when I get the chance.

You could always try other objects which are brighter and gauge how the lens performs wide open.

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Old 18-01-2009, 07:13 PM
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Octane (Humayun)
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Trevor,

When I imaged this object using a 300mm lens, it occupied 2/3rds of the frame, if that's anything to go by.

Here's a 50mm lens example.

I hope this helps.

Regards,
Humayun
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Old 19-01-2009, 06:37 AM
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madwayne (Wayne)
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Trevor

As a suggestion, would the LMC be a better candidate for you? Plenty big and bright enough .

Good luck and I hope my two cents worth is of value.

Wayne
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Old 19-01-2009, 10:38 AM
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Hi Trevor,
Here is a recent witch head at 98mm FL, should give a close indication of your expected FOV
Doug
Attached Thumbnails
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Old 19-01-2009, 10:59 AM
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Quote:
Originally Posted by Octane View Post
Trevor,

When I imaged this object using a 300mm lens, it occupied 2/3rds of the frame, if that's anything to go by.

Here's a 50mm lens example.

I hope this helps.

Regards,
Humayun
Thanks Humayan,

Yes it does help, what great images you have done, yet again.
I was most surprised at how this region came up with your 50mm effort.

Regards
Trevor
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Old 19-01-2009, 11:00 AM
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Quote:
Originally Posted by madwayne View Post
Trevor

As a suggestion, would the LMC be a better candidate for you? Plenty big and bright enough .

Good luck and I hope my two cents worth is of value.

Wayne
Hi Wayne,

Thanks for the reply, the LMC is definetly on my list of. to do objects.

Regards
Trevor
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Old 19-01-2009, 11:03 AM
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Quote:
Originally Posted by dugnsuz View Post
Hi Trevor,
Here is a recent witch head at 98mm FL, should give a close indication of your expected FOV
Doug
Thanks Doug,
Top effort.

I think images such as this really underline just how extensive this object really is, looking forward to having a crack at it.

Regards
Trevor
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