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My Telescopes

My Main Telescope - C14 and Paramount ME

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

MyT Hand Controller

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 188 Friday 3rd October Lightning strike. Is my equipment damaged? | Main | Day 186 Wednesday 1st October 2014 Transforming the QX Cas photometry. »

Day 187 Thursday 2nd October 2014 Cepheid Variable CF Cas Calculation of its apparent Magnitude and Colour Inde

NGC 7790 contains three Cepheid Variables as shown in the AAVSO Chart. CE Cas A and B are variable elements of the same double star and very close so not within my equipment's ability to separate them to measure their magnitude. This paper "CE Cas a, CE Cas b, and CF Cas in NGC 7790" by J. Smak in 1966 looked at all three variables. This paper followed by Allan Sandage et al. in 1969.


This is my image in VPhot with the target, comparison and check stars shown and an expanded view of CF Cas


 This is the result of the untransformed photometry


 I repeated the photometry with the B image of NGC 7790 and obtained a B magnitude of B = 11.598

So B - V = 0.409.

I will continue with this star in future blogs.