[Mr Ian David Sharp]

Hi Kevin,

Section 3.3.10 in the AAVSO CCD/CMOS Photometry guide is very informative with regards to the Gain and Offset settings in CMOS cameras:

https://www.aavso.org/sites/default/files/publications_files/ccd_photometry_guide/CCDPhotometryGuide.pdf

Once you choose a gain and offset, just stick with it for all lights and calibration files.

With regards to temperature, just go with a value that your camera can cool to reliably. I use both -10C and -20C with my CCD. I use -10 in the Summer months when I find the camera can’t cope with -20. I have a QHY268C CMOS camera which I image with and I find that it can’t get down reliably cooler than -15C, so I tend to stick with -10.

Binning – I use both 1×1 and 2×2 for fainter targets.

Cheers
Ian.

[Mr Ian David Sharp]

Hi Kevin,

I forgot to mention that I used an Alnitak Flip-Flap on my 104mm refractor setup at PixelSkies in Spain. See photos and details here:

http://www.astro-sharp.com/2021/10/23/my-new-remote-setup-in-spain/

This was brilliant because I could control it remotely. I have recently replaced the OTA with a C11 and now I have to ask the folks there to place a light panel on to the C11 when I need to refresh my flats (which is not very often).

Cheers
Ian.

[Mr Ian David Sharp]

Hi Kevin,

For what size OTA?

I use LED flat panels for my kit (is that what you mean by a pad?). I have an A3 size panel which covers my C11 ok. I have a smaller Pegasus Astro Flatmaster panel which covers my refractors and is dimmable and USB controllable. There are lots of choices of LED Flat panels out there now.

These look nice: https://www.widescreen-centre.co.uk/aurora-flatfield-panels.html

Cheers
Ian.

[Mr Ian David Sharp]

Hi all,

It looks to be slowly dimming again. I got Vmag = 11.62 and Bmag = 12.42 last night. See attached.

Cheers
Ian.

Attachments:

1. 

   V426-Sge-20231019.png
   

[Mr Ian David Sharp]

Thanks for the info Gary,

I managed a decent set of R, V and B last night from Spain. V mag was coming out at around 14.6 with R at about 14.2.

All uploaded into the dB.

Cheers
Ian.

[Mr Ian David Sharp]

Hi all,

I got some nice results last night in B and V – 10 images of each. I get 11.43 in V and 12.16 in B and it looks to be brightening from David and Gary’s recent points. See attached.

Cheers
Ian.

Attachments:

1. 

   V426-SGE.jpg
   

[Mr Ian David Sharp]

Thanks for the heads up David,

I’ve set up a run from Spain in B and V tonight…

Cheers
Ian.

[Mr Ian David Sharp]

Hi all,

My B mag. measurements from last night suggest a bit of a rise in the past few days. Hope to check this again tonight.

Attachments:

1. 

   T-Crb-20230920-ids.jpg
   

2. 

   20230920_T-CRB_B_PixelSkies-C11_IDS_plot_points.png
   

[Mr Ian David Sharp]

Wow! Just been watching Brad Schaefer’s presentation. This is so exciting! Now I understand why the call for B-band photometry.

Marvellous!

Ian.

[Mr Ian David Sharp]

Jeremy Shears wrote:

They said there would be a video available shortly.

Here it is: https://fb.watch/mZhv9T6ax3/

Cheers
Ian.

[Mr Ian David Sharp]

Gary Poyner wrote:

Certainly looks like it Ian. My efforts attached.

Hi Gary,

Excellent!

Here’s my update as of last night. I had three rainy nights in a row in Spain!

Cheers
Ian.

Attachments:

1. 

   SN2023ixf_05_Sep_ids.jpg
   

[Mr Ian David Sharp]

Many thanks Andrew and Kevin,

I’m coming around to the idea!

Best Regards
Ian.

[Mr Ian David Sharp]

Thanks Jeremy,

I managed to get an 11th mag comparison star in the FOV and that has improved things.

Here’s another 2 hour B run from last night.

Cheers
Ian.

Attachments:

1. 

   T-Crb-20230825-ids.jpg
   

[Mr Ian David Sharp]

Hi Jeremy,

I’ve been monitoring T CrB for a couple of months in R, V and B and have noticed much more variability in B, but it has not made any significant shifts until last night when I managed a longer run over about 2 hours. See the attached graph.

The problem I have so far is that my reference and check stars are a good 2 mags. fainter because of the tight FOV of my C11 setup. I’ll try and offset the FOV a tad to fit in a brighter ref star or two.

Cheers
Ian.

Attachments:

1. 

   T-Crb-20230824-ids.jpg
   

[Mr Ian David Sharp]

Kevin West wrote:

Are these suitable to get started in CMOS photometry. Does anyone in BAA have experience of using them?

Hi Kevin,

Yes, I use these filters, but I only use the R, V and B. I would forget ‘U’, but the ‘I’ can be useful. I use them with a CCD camera, but no problems with a CMOS camera.

As well as photometry, I also use them for colour imaging as there is not enough room in my 7-pos filter wheel for a standard set of RGB filters. I have the following filters: L, R, V, B, Ha, OIII, SII, and this works very well for everything.

Best Regards
Ian.

• This reply was modified 1 year, 10 months ago by Mr Ian David Sharp.

[Mr Ian David Sharp]

Hi all,

Last night’s results seem to suggest the start of a plateau? See attached graph.

Best Regards
Ian.

Attachments:

1. 

   SN2023ixf_16_Aug_ids.jpg
   

[Mr Ian David Sharp]

Jane Clark wrote:

In addition, I think we can make your “It’s turned back up again!” statement a little more quantitative.

Hi Jane,

Yes, of course my comment was conversational, if a bit glib!

I’ve sent you a PM with the Excel file attached.

Ian.

[Mr Ian David Sharp]

Robin Leadbeater wrote:

I see from the light curve the slow steady decline (~2 magnitudes in V over 70 days) has come to an end and the brightness is now dropping rapidly (~1.5 magnitudes in 12 days)

Hi Robin,

Yes, and it’s turned back up again! See attached graph as of last night’s data…

Cheers
Ian.

Attachments:

1. 

   SN2023ixf_14_Aug_ids.jpg
   

[Mr Ian David Sharp]

Hi all,

With regard to may last post. New data from last night reveals that the slow decline continues!

Ian.

[Mr Ian David Sharp]

Yes indeed, an excellent day!
Ian.

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