[Mr Ian David Sharp]

Now all my R and V data from last night is in the database. Here’s a zoom in to it.

Ian.

Attachments:

1. 

   ss_cyg_baa_out2.png
   

[Mr Ian David Sharp]

Mr Ian David Sharp wrote:

I’ve processed one set of V and one of V so far.

Should be R and V – sorry.
Ian

[Mr Ian David Sharp]

Yes!! I’m thrilled!

I captured 120 exposures in both R and V last night here in the UK and also in Spain. I’ve processed one set of V and one of V so far. See the attached light curves from both AAVSO and BAA databases. I’ve caught the rise right in the middle by the looks of things.

Ian.

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1. 

   ss_cyg_aavso_out1.png
   

2. 

   ss_cyg_baa_out1.png
   

[Mr Ian David Sharp]

Thanks Gary,

I’m going to image it as long as I can tonight from here and Spain. Maybe I will detect a brightening over the night?

Ian.

[Mr Ian David Sharp]

My years ago, when I was a Physics undergraduate, we were shown this marvellous film (projected on film of course).

https://youtu.be/tbsdrHlLfVQ?si=VEQ55jLdgto6QjVU

[Mr Ian David Sharp]

Thanks Robin,

I measured it at V=14.59 and R=14.52 last night (2024-01-31 00:30)

Cheers
Ian.

[Mr Ian David Sharp]

Hi all,

Difficult to quantify, but one statistic I can quote is that I submitted 37,974 variable star measurements to the BAA Photometry database during 2023. This may sound a lot, but I regularly upload 100+ data points in any one observation as I focus on PCEB systems.

It’s only because I have a system in Spain that I was able to do this. Having said that, there was a period from late May for 6 weeks in the UK where I had almost entirely clear skies.

Cheers
Ian.

[Mr Ian David Sharp]

Tony Vale wrote:

Have you tried the AAVSO ? I may be mistaken but I seem to remember that Bert Pablo, the staff astronomer, had some involvement with the development of PHOEBE2.

Hi Tony,

That’s a very good idea – thanks, I might try that.

In actual fact, I have persisted with this myself and I am now making quite good progress. I have finally managed to understand some of the key concepts and am getting some results out of Phoebe. This is good as I won’t have to ask so many very basic questions if I do contact someone.

Cheers
Ian.

[Mr Ian David Sharp]

Michael O’Connell wrote:

Folks,
My initial thoughts after successfully observing the occultation last night:

Excellent! Certainly more interesting than my drift trail!

Cheers
Ian.

[Mr Ian David Sharp]

Well, here’s my 60 second drift image with an OIII filter. I had no saturation (this image is slightly stretched). I see no sign of any dimming.

Cheers
Ian.

Attachments:

1. 

   betel_occult.png
   

[Mr Ian David Sharp]

Alex Pratt wrote:

Drift is a good option. Driftscan software can process your capture. Please record for about 1 minute before and after the mid-time given by the Interactive Map of the Paris ‘Lucky Star’ prediction

Thanks Alex,

I’m experimenting now. I can record (drift) for just over a minute which will be only 30 seconds or so either side of my predicted mid time. The only filter that does not saturate is my OIII giving me ADU values of about 30,000.

Cheers
Ian.

[Mr Ian David Sharp]

Hi all,

It looks like the occultation track of Leone tonight passes over my telescope at PixelSkies in Spain.

Having a C11 with an SX694 TRIUS CCD, I can’t take short, rapid exposures a la a CMOS camera, so my plan is to let it drift across the FOV. I will experiment first with am R filter but I suspect it will easily saturate. Then I will try an SII. All slightly off focus I think.

Any other tips?

Cheers
Ian.

[Mr Ian David Sharp]

Hi Grant,

Yes, I have several mini PCs on my various rigs. I like the ones from Beelink and also the MELE Quieter series which are fanless and silent.

This Beelink is under 200 quid! : https://tinyurl.com/bddzz49d

Cheers
Ian.

[Mr Ian David Sharp]

Thanks Nick,

Here’s my image from last night.

Cheers
Ian.

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   12p_20231119_182722_ids.jpg
   

[Mr Ian David Sharp]

I also got another image last night. I captured the dark streak nicely, but my processing does not seem to have shown the blobs.

Cheers
Ian.

Attachments:

1. 

   12p_20231116_182735_ids.jpg
   

[Mr Ian David Sharp]

Thanks Robin,
Ian.

[Mr Ian David Sharp]

Hi all,

I managed to image 12P last night from Spain. Here is a stack of 20 x 60 secs with an L filter. North is to the left. Image is 18′ x 14′ (0.48 “/pix).

The nucleus is very bright!.

Cheers
Ian.

Attachments:

1. 

   12p_20231116_182724_ids.jpg
   

[Mr Ian David Sharp]

Kevin West wrote:

I don’t know what stretching is.

Ah! then you have to learn about this!

Astronomical deep-sky images contain mostly black (or near black) sky. When you view an image un-stretched astronomical image you see virtually nothing – just a few pin pricks of light from the brightest stars. This is because most of the data is residing near the black-point of the ‘histogram’. But applying a non-linear stretch to the image, the data is spread more evenly across the histogram from the black point to the white point.

See my attached screen shot. The image on the right is a clone of the one on the left but I have applied a histogram stretch to the one on the right. Without this skill you will not be able to see your data properly, nor be able to check the calibration properly.

I feel you have learning curves all over the place! If you would like a Skype or Zoom (or similar) call I could share my screen and take you through a few things? Otherwise there will be a lot of back and forth with messages etc.

You can PM me here if you want to set something up…

Cheers
Ian.

• This reply was modified 1 year, 9 months ago by Mr Ian David Sharp.
• This reply was modified 1 year, 9 months ago by Mr Ian David Sharp.

Attachments:

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   stretch.png
   

[Mr Ian David Sharp]

Hi Kevin,

Further to this, as Grant has mentioned, compare your uncalibrated lights to your calibrated lights. See my attached image where I show three heavily stretched images. Top left is uncalibrated – note the gradients and the dust marks. Top right is calibrated – note it looks pretty flat. Bottom is the flat frame with a big stretch.

Not the most dramatic example because my C11 has a pretty flat field over this sensor to start with. But – I must try and get rid of that horrible splodge on the sensor!

Cheers
Ian.

• This reply was modified 1 year, 9 months ago by Mr Ian David Sharp.

Attachments:

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   calib.png
   

[Mr Ian David Sharp]

Kevin West wrote:

So the image it outputs, is that a calibrated image? Is it possible to tell?
What does the software do to the original uncalibrated lights?

Hi Kevin,

ASTAP does nothing to your uncalibrated lights and it creates calibrated copies with “_cal” on the end of the file names.

If you look at the FITS headers of the calibrated files, you will see something as shown below towards the end of the header. In my test I only selected my master dark and master flat files and you can see resulting CALSTAT = ‘DF’. Also the COMMENT 1 field indicates it was calibrated by ASTAP.

What do you see in the CALSTAT field when you use your flat-darks?

Cheers
Ian.

COMMENT 1 Calibrated by ASTAP. http://www.hnsky.org
PEDESTAL= 5.000000000000E+002 / Value added during calibration or stacking
CALSTAT = ‘DF’
DARK_CNT= 1 / Darks used for luminance.
FLAT_CNT= 1 / Flats used for luminance.

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