andrew s

You can use cat5/6 cable in many ways. You can use it from an obs computer to a network router and access your computer via remote access software over your local area network. You can run USB over it with suitable converters or even remote mouse keyboard and screen via keyboard extenders. I have done the first and last option but not tried USB. I would put two cables in if I were you. Regards Andrew

Prof Nat Bastian gave a brilliant talk on Globular Clusters at Chester Astro Soc last night. He completely revised what I thought we new about them. In his talk he showed simulations from the Eagle Project http://icc.dur.ac.uk/Eagle/downloads.php and from the E-Mosaics Project http://www.astro.ljmu.ac.uk/~astjpfef/e-mosaics/downloads which combine his groups work on cluster formation with the cosmological evolution simulations of Eagle. The downloads are not the exact same ones shown but if you have not seen them the they are well worth a look. Regards Andrew

Unfortunately, the zero order is not on any standard photometric system as it is the residual left after the spectra have been diffracted out. Nevertheless, it can save me looking at thousands of images one by one! Regards Andrew

I have started looking to get low resolution spectra of Red Dwarf stars during a flare. However, they are not frequent and I wanted to test my strategy of finding a flare by doing photometry on the zero order image. To this end I decided to look at CW Cas an eclipsing binary and follow the exact procedure of aligning the frames then doing multi-star photometry with out any calibration in astroimagej. The result is attached. There were light clouds at times hence the increase in noise in places but I was pleased with the result. (The gap is a meridian flip.) All was done automatically using CCDAutoPilot5 and The Sky X while I attended the Chester Astro Soc meeting and then slept. Regards Andrew

I forgot previously but when my observatory burnt down taking everything with it I should gave had a killer moment. However, the insurance paid up and I had weeks of joy choosing new kit as a coherent set. I ended up with a better set than I started with. Regards Andrew

Found a paper "more realistic description of wave front distortions by atmospheric turbulence " try googling it . Regards Andrew

How many clear nights a year? Regards Andrew

Sky & Telescope had an article on astro hobby killers. So I was wondering what nearly killed the hobby for you? For me it was working in the North East near Middlesborough where the industry at the time ensured a bright orange sky. Coupled with my poor eye sight I could never find anything beyond the moon and planets. Regards Andrew

The internet link to castillejar is limited and via satellite so I do all my pre processing on my local machine to limit the data transfer. Mark you I took 1852 x32 Mb images last night! Most likely none will be transferred as I am looking for transient flares. Regards Andrew

If so it's accidental. I am not that subtle. Regards Andrew

@Paul M Gravity is a force in Newton's theory but not in Einstein's general relativity. You pays your money and takes your choice. Regards Andrew

The paper describing the observation on which this is based gets a poor reception on Physics forum. It seems they come up with new breakthroughs all the time that are not substantiated . Might be true but don't hold your breath. Work is ongoing in many areas "beyond the standard model" . Regards Andrew

It's focal length that is important, longer than the collimator if possible. Nothing to sweat over. It's best to set it as well as you can to get parallel light onto the grating. Then you focus the spectra onto the ccd with the camera lens. Regards Andrew

Just having my first. I was just about to add it is best if the telescope or camera has a ( much) longer focal length than the collimator as this reduces the error in setting the collimator. I uses on old f10 guide scope with a reticule eyepiece . Others e.g. C Buil have used a DSLR with telephoto lens. Regards Andrew

The guide camera should focus on the slit. You then focus the star on the slit using the telescopes focuser (optimal throught put may be slightly out of focus). To get the collimator focused on the slit you can use several methods but they amount to observing the slit via the collimator wth a camera or telescope focused at infinity. Exactly how to do the will depend on the layout and may need a folding mirror or even using the grating. Regards Andrew

If you Google "Are stars forming in the Orion nebula " you get links that say not at the moment due to the wind from a newish star. However, this is producing high density areas where they will in future. Regards Andrew

It better not work. Regards Andrew

As you expose a ccd it goes through 4 regimes. Initially it is read noise dominated. This is followed by photon/shot noise which is proportional to the square root of the signal. Next comes the region dominated by pixel response non uniformity (PRNU) which is proportional to the signal level. Finally we reach saturation where the ccd's (near) linear response to light no longer holds. Once you reach the PRNU region extra signal does not improve the SNR you need high quality flats to remove the PRNU noise. Regards Andrew

On the science front again you might want to consider at least a V band photometric filter if there is room. A number of people on SGL have done photometry. Timing extrasolar planet transits requires long runs which are difficult to get in the UK. Finally you could add a SA200 grating to allow people to try spectroscopy. Regards Andrew

@vlaiv I was trying to point out that even with a noiseless perfect detector there will be variation in the measured arrival rate due to the physics of photon statistics. On top of this there will be noise added by the measurement process. So on top of the 1/6 die face we have reading errors e.g. mistaking a 5 for a 6. Regards Andrew

I noticed you are planning some scientific imaging. If you need precise timing I have a gps time server on the local area network in Castillejar which you can use to discipline you PC's clock. If you are interested PM me and I will send info on how to access it. Regards Andrew

Glad you will be joining my equipment in Castillejar just don't bring bad weather with you. Great initiative, we need ways to sidestep the UK perma-cloud. Regards Andrew

@vlaiv photon detection is a fundamentally quantum process. You can't think of a star emitting photons which travel to earth and are then detected on earth. This mixes the QM and classical views. In QM there is a probabilty that photons are created at the star and given that a probability the will be detected (annihilated) here on earth. This is process is fundamentally probabilistic. Measurements over time will converge to the average but will always retain some uncertainty for any real example. Regards Andrew

Opps quite right boson and Bose Einstein statistics. Not sure what I was thinking but still approximates to poisson statistics with clumping 😱 Regards Andrew

Photons are Fermions and follow fermi dirac statistics which for optical wavelengths approximates to poisson statistics. The "arrival times" are correlated in that the if a photon is detected it increases tha probability another will be in a given time interval. This effect is significant at radio wavelengths. Given @vlaiv comments his question is unanswerable without a clear definition of his terms. Regards Andrew Sorry bosons and Bose Einstein statistics