bahtinov mask: no spikes

[alacant]

Hi

When viewing through a dslr attached to a telescope, I see stars e.g. Sirius, as points, as if the mask were not there. Do the masks work with dslrs?

TIA

[steppenwolf]

They do indeed work with the DSLR cameras but you will need a bright star to allow you to see the diffraction pattern.

Have you considered using software like EOS Movie Record which has a x5 Zoom to allow you to examine the star zoomed in? This software works with Canon and to the best of my knowledge there is a Nikon version too.

[rubecula]

Yes they do, here's an image of the mask (cropped quite a bit) taken with a Canon 7D camera:

[alacant]

OK, thanks. I must be doing something wrong, although I must admit to not knowing what.

[Thalestris24]

15 minutes ago, alacant said:

OK, thanks. I must be doing something wrong, although I must admit to not knowing what.

Hi

I recommend using APT which has a Bahtinov mask tool that gives you a magnified image of the star plus data. You do need a fairly brightish star (but not too bright!) to focus on in APT. Sometimes liveview doesn't cut it and you have to take multiple short exposures but normally I expect you'll have a bright enough star visible.

Louise

[Ken82]

Use digital zoom on the dslr

[hjw]

Hi TIA,

When I use my Bahtinov mask on my DSLR I do not see any spikes, even on bright stars. However, I do see a diffraction pattern. When in focus, the star has two crescent moons on each side, when out of focus the pattern is no longer symmetrical. I tried to draw an image of what I can see ( under max. zoom preview). In focus is the pattern in the center:

Clear skies!

HJ

[Scott]

11 minutes ago, hjw said:

Hi TIA,

When I use my Bahtinov mask on my DSLR I do not see any spikes, even on bright stars. However, I do see a diffraction pattern. When in focus, the star has two crescent moons on each side, when out of focus the pattern is no longer symmetrical. I tried to draw an image of what I can see ( under max. zoom preview). In focus is the pattern in the center:

Clear skies!

HJ

HJ, is this with a camera lens or the scope? I've always had the spikes with the scope and dslr

[glowingturnip]

i usually take say a 10 second exposure in APT, which is enough to show spikes

[craigg]

I find using the camera in video mode with manual settings works best for me (canon DSLR) rather than the live view.  Set the ISO as high as it goes, increase exposure to max (prob 1/30).  Then, as others suggest, use the digital zoom to zoom in on the star.  Once focussed, remove the mask, set ISO to taste, and switch to manual mode.

[Stub Mandrel]

Max ISO and long exposure (so the DSLR 'simulates' it).

[Dbswales]

On 11 April 2016 at 15:33, Thalestris24 said:

Hi

I recommend using APT which has a Bahtinov mask tool that gives you a magnified image of the star plus data. You do need a fairly brightish star (but not too bright!) to focus on in APT. Sometimes liveview doesn't cut it and you have to take multiple short exposures but normally I expect you'll have a bright enough star visible.

Louise

I agree with Louise. I use this every time and it's foolproof. Only problem I get is that I've been know not to remove the mask before starting g the imaging!