Observation by Grant Privett: Unsharp M81

Uploaded by

Grant Privett

Observer

Grant Privett

Observed

2022 Jan 22 - 22:00

Uploaded

2023 Oct 22 - 00:43

Objects

M81

Equipment

300mm VX12 f/4 Newtonian
SW NEQ6 with Rowan Belts
SX Trius 694

Exposure

240x 30s

Location

Near Salisbury

Target name

M81

Title

Unsharp M81

About this image

A good while ago I took a nearly first light image with the 12". The coma corrector was at the wrong backfocus, the collimation was way out and the focus was abysmal, but after days fighting the mount, TSX throwing a wobbly and bad comms I didn't care and took a half decent M81 (if you like soft focus galaxies). Anyway, about then Paul Leyland took a picture showing a whole bunch of globular clusters in M81 (mainly mag 19-21) and since then I've been meaning to check my image.

The evening following an afternoon of swearing at Indi/Alpaca/ASCOM meant I finally gave it a go. I didn't do the thorough job he did but did show they are within range of the 300mm aperture certainly and, I suspect a 200mm or 250mm could catch a few them. Something for someone fancying a challenge.

To make things easier to see, I used an unsharp mask to remove some of the continuum of the galaxy.

Files associated with this observation

m81-unsh-anno.jpg (489.1 kB)

Like this image

Dominic Ford, Mattia Piccoli, Graham Winstanley, Dr Paul Leyland, Callum Potter

Comments

Dr Paul Leyland, 2023 Oct 24 - 10:52 UTC

I'm certain a 200mm could get them. You used only 2 hours exposure. (300/200)^2 = 2.25 so 4.5 hours should get much the same as your image. That could be done in a single night, though imaging over several nights may be easier in some ways.

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