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My Main Telescope - C14 and Paramount ME

My new Paramount MyT and 8-inch Ritchey-Chretien Telescope

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My Meade 12 inch SCT on a CGEM (Classic) Mount

My 4 inch Meade Refractor with Sky Watcher Guidescope and ZWO camera on a CGEM (Classic) Mount

Skywatcher Star Adventurer Mount with Canon 40D


My Solar setup using a DSLR and Mylar Filter on my ETX90

DSLR attached to ETX90. LiveView image of 2015 partial eclipse on Canon 40D

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 I try to log my observing and related activities in a regular blog - sometimes there will be a delay but I usually catch up. An index of all my blogs is on the main menu at the top of the page with daily, weekly or monthly views. My Twitter feed is below. I am also interested in photograping wildlife when I can and there is a menu option above to look at some of my images. I try to keep the news feeds from relevant astronomical sources up to date and you will need to scroll down to find these.

The Celestron 14 is mounted on a Paramount ME that I have been using for about 10 years now - you can see that it is mounted on a tripod so is a portable set up. I still manage to transport it on my own and set it all up even though I have just turned 70! It will run for hours centering galaxies in the 12 minute field even when tripod mounted.


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« Day 186 Wednesday 1st October 2014 Transforming the QX Cas photometry. | Main | Day 184 Monday 29th September 2014 QX Cas is suspected of ceasing its variability - I investigate by measuring its current magnitude. »

Day 185 Tuesday 30th September 2014 Photometry of LP Cam in NGC 1502

I used telescope T21 in New Mexico to take B and V images of the open cluster NGC 1502. The images were 90 second exposures. [I intend to transform the measured magnitude of a variable star in the field so I needed V and B images to be able to apply the transformation coefficients that are supplied by]

This is the cluster using a B filter

 This is the cluster using a V filter




This is the V image of NGC 1502 loaded into VPhot. 

 I aim to obtain the current magnitude of the variable star LP Cam and have designated a comparison star and check star as shown. BD+61 675 is the comparison star which has a V magnitude of 9.62 and Tycho 4068:1471 is the check star with a V magnitude of 11.15 from the Tycho catalogue. 

The comparison star had some close neighbours - this is how I positioned the annuli. The central circle takes in just the star and the nearby stars are all positioned in the gap. The outer annulus only includes sky background which is subtracted from the signal in the inner circle (based on the same sky signal per pixel) to give just the flux from the star. The central circle is the same radius of 10 pixels (essential that they are the same) as the other two stars concerned but the outer annulus varies as shown - the scale is different for each image with a common 10 pixel central circle radius.



This is the photometry report

So the untransformed V magnitude of the target is 11.168