Back in the 90's I recorded the apparent magnitude of a number of stars known to change their brightness, sending off the information to the British Astronomical Association (BAA). To record the magnitude, I used a pair of binoculars to find the star via a chart provided by the Variable Star Section of the BAA. I then compared the brightness of the target star with stars of known brightness that did not change. All this ended when I broke my binoculars and , at that time, I was not able to afford a new pair.
Zoom to present day.
Two things, one being I have thought I would resume taking some variable star measurements, plus, we are going on holiday to Aquitaine where there should be really dark skies. I toyed with the idea of buying a pair of Celestron 20 x 80 binoculars, but in the end decided the steadier platform of a small Dobsonian would be more pleasurable to use. So, I bought a second hand Sky-Watcher Heritage 130P FlexTube Dobsonian Telescope. It looks like a toy, but has a 1300 mm parabolic mirror that is really good quality. Marrying this to y Televue 25 mm Plossl or BST 25 mm Starguider and optically, I have a very nice telescope indeed. It is very portable, easy to use for star hopping, has a field of view of just under 3 degrees (with the BST 25 mm Starguider eyepiece) and the only electronics are the red dot finder.
I did a few mods, one ot add some thick grease to the helical focusser, to remove the slop, to add a couple of velcro patches to make the telescope tube cover more likely to stay on and to add a little extension piece and a bigger red dot finder to make it more usable, especially for targets close to the zenith.
I have used it to take a few readings of X Herculis and AC Herculis.
I have also tried doing some DSLR Photometry, with the Skywatcher 80 ED Pro. That involves finding the traget variable star (via Carte Du Ciel), defocussing, then taking images but making sure the stars are not saturated. I have had one attempt so far, but I think I defocussed too much ( 1 1/2 turns of the fine focus). When I tried using IRIS (from AAVSO), it had problems identifying stars at the registration stage.
So, next time, I shall be trying iso 400, 30 s exposures and 3/4 turn fine focus to defocus.
Zoom to present day.
Two things, one being I have thought I would resume taking some variable star measurements, plus, we are going on holiday to Aquitaine where there should be really dark skies. I toyed with the idea of buying a pair of Celestron 20 x 80 binoculars, but in the end decided the steadier platform of a small Dobsonian would be more pleasurable to use. So, I bought a second hand Sky-Watcher Heritage 130P FlexTube Dobsonian Telescope. It looks like a toy, but has a 1300 mm parabolic mirror that is really good quality. Marrying this to y Televue 25 mm Plossl or BST 25 mm Starguider and optically, I have a very nice telescope indeed. It is very portable, easy to use for star hopping, has a field of view of just under 3 degrees (with the BST 25 mm Starguider eyepiece) and the only electronics are the red dot finder.
I did a few mods, one ot add some thick grease to the helical focusser, to remove the slop, to add a couple of velcro patches to make the telescope tube cover more likely to stay on and to add a little extension piece and a bigger red dot finder to make it more usable, especially for targets close to the zenith.
I have used it to take a few readings of X Herculis and AC Herculis.
I have also tried doing some DSLR Photometry, with the Skywatcher 80 ED Pro. That involves finding the traget variable star (via Carte Du Ciel), defocussing, then taking images but making sure the stars are not saturated. I have had one attempt so far, but I think I defocussed too much ( 1 1/2 turns of the fine focus). When I tried using IRIS (from AAVSO), it had problems identifying stars at the registration stage.
So, next time, I shall be trying iso 400, 30 s exposures and 3/4 turn fine focus to defocus.
lovely bit of decking that
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