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 Post subject: Re: Astrophotography...
PostPosted: Tue, 10-04-18, 9:09 GMT 
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fenerit wrote:
I would suggest also a shot to the nearby galaxy NGC 4631 (Whale galaxy) still in Canes Venatici and NGC 4565 (Needle galaxy) in Coma, they are good subjects for your equipment.

I'll put them on my observation list ;)
Apparent magnitude of 10.42 (NGC 4565) is a bit of a challenge with my exposure times though. But I'm trying to get a used EQ-6, which should allow for longer exposures with less rejects.

fenerit wrote:
A good 2x Barlow linse maybe could be your next acquisition, inserted between the coma corrector and the camera it does extend the focal lenght of the scope and you will go closer.

I thought about this, but I was not sure if it wouldn't simply enlarge the image (or reduce the FOV), without actually helping to get more details? I felt that I was already oversampling the resolution provided by the 6" with the APS-C camera sensor...
Do you have a link to some good Barlow?
Depending on the costs, it could be better to invest in a larger scope - but that's for the more distant future.


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 Post subject: Re: Astrophotography...
PostPosted: Tue, 10-04-18, 22:23 GMT 
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schreiberste wrote:
Apparent magnitude of 10.42 (NGC 4565) is a bit of a challenge with my exposure times though. But I'm trying to get a used EQ-6, which should allow for longer exposures with less rejects.

NGC 4565 has about the same magnitude of NGC 3628 (fainter Leo Triplet's component) but it is more luminous by far (read: its surface brightness), so it is possible you get lots of good samples. Of course with a better mount will be easier.

schreiberste wrote:
I thought about this, but I was not sure if it wouldn't simply enlarge the image (or reduce the FOV), without actually helping to get more details? I felt that I was already oversampling the resolution provided by the 6" with the APS-C camera sensor...
Do you have a link to some good Barlow?
Depending on the costs, it could be better to invest in a larger scope - but that's for the more distant future.

There are two kinds of Barlow lenses:
1) classic Barlow
2) telecentric Barlow
with some subtilety optical differences, the preminent is the number of the lenses' group. You can find some explanations here. Their prices are in range 150-250€ for 2inch quality 2x focal extenders.

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 Post subject: Re: Astrophotography...
PostPosted: Tue, 10-04-18, 23:14 GMT 
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About NGC 4565, you can compare the image below with that of NGC 3628 shown in the first page of this thread. NGC 3628 was 20x120sec. luminance, binning 2x2: 40min. total. Below is 3x10min. luminance, binning 2x2: 30min. total. Because you got a stunning image of NGC 3628, I do not see why you can't get also this beautiful galaxy. With averted vision this galaxy does stretch the spiral "tips" very apparently gaining brightness.
Attachment:
Ngc4565.jpg
Ngc4565.jpg [ 277.78 KiB | Viewed 91 times ]

3x10min. luminance, binning 2x2, some miscollimation

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 Post subject: Re: Astrophotography...
PostPosted: Wed, 11-04-18, 6:35 GMT 
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OK, now NGC 4565 moved up a bit on my todo-list ;)
But I'll have another go at M101 before, which should be far easier in any case!


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 Post subject: Re: Astrophotography...
PostPosted: Wed, 11-04-18, 9:39 GMT 
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schreiberste wrote:
OK, now NGC 4565 moved up a bit on my todo-list ;)
But I'll have another go at M101 before, which should be far easier in any case!

M101 is a very low surface brightness galaxy; visually, I don't like it too much, faint spiral arms and seeing dependent. Good catch!

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