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Found 20 results

  1. Hello all, I am looking into making a hobby out of spectroscopy but don't exactly know where to start. All I can really go off is a high school education of physics and the various reading that one usually does when looking into something new. The main questions are, essentially; 1. What is the best spectrometry equipment for an amateur like myself? I have little to no knowledge on all the necessary equipment, so any recommendations would be very much appreciated. For any suggestions, if you wouldn't mind giving a reason as to why you recommend a said product, I will take this information with great appreciation. In terms of a camera, I've read that CCD monochrome cameras are the best. How does a DSLR rank against this though? In terms of a telescope, should I be looking at one with a specific aperture range? If so, are there any other properties I should be looking at? Is a grating better than a prism? Why? What software is the most effective and easiest to use? Do I need some sort of focusing device? 2. How do you collect spectral data using the technology? Is it as simple as pointing at a star and recording the acquired data? How long should I view the chosen star? Is it a photo or a video? I would assume that these questions have been asked plenty of times, so any links to other forums which discuss the same questions and topics I am raising will be very helpful as well. Any type of reply is welcome. As an amateur, anything is helpful. Looking forward to discussing this with you all. Monte.
  2. I've called it LOWSPEC.2 as it's the updated version of Paul Gerlach's LOWSPEC, a DIY 3D printed spectrograph. I built the first version but had trouble aligning the guide mirror (which was fixed), and locating the slit by waving a torch down the scope made it difficult to use. The updated version is a vast improvement, for me at any rate. 1. The guide mirror can now be adjusted forward and backwards and side to side. I can now actually guide the spectrograph. 2. Adding an Illumination device (Baader). The slit can now be illuminated and the overlay in PHP2 used to locate it. No more trouble getting the star on the slit. There is also the option to use a 30mm dia camera lens instead of 24mm. The camera lens used is 100mm focal length; I had a 30mm dia lens left over from a previous diy project which is 90mm focal length so I used that. I'm not sure of its quality as I bought it for £15 from ebay, but it seems to work ok. I also had a defraction grating of 600 l/mm from a previous project so used that. Paul reckons LOWSPEC will now cope with anything up to a grating of 1800 l/mm. For calibration I used a Philips S10 starter bulb because I found some calibration charts for it, (I think on one of the French websites) and these bulbs are about £1 in B & Q, significantly less than the Relco ones (if you can get them). I made a hole in the top cover, made a container on the 3D printer and now I simply insert it when I need to get a calibration reading. Not the most practical solution but again, it seems to work. If Paul manages to add a calibration unit inside LOWSPEC, that would be the icing on the cake. And if it could just be attached to the existing body that would be a bonus, as it took me 29 hours to print! Here's a couple of shots of the thing itself. The long tube houses the Philips lamp. Here the calibration unit is inserted into the top cover. The first reasonably clear night was moonlit and there was high cloud coming and going, but I went first for Vega as it's easy to image and calibrate with the Hydrogen lines. The salmon coloured line is the A0V reference. The image of Vega looked quite good on the laptop, so I moved on to P Cygni, one of my favourite subjects, and here are the results. I've taken some of the readings from a PDF version of Richard Walker's 'Spectroscopic Atlas for Amateur Astronomers'. It doesn't seem to be available for download any more, I think there's now a book which you have to buy. I may need to get a better guide camera; I'm using an Altair Astro GPCAM mono and when guiding it used a star with a S/N ration of 9.8, the brightest available. But having said that, it managed to keep P Cygni on the slit for 5 minutes at a time. LOWSPEC is a great project if you've started out using the StarAnalyser and want to move to a higher resolution. It takes a lot of patience and persistence, but worth it. I reckon the total cost for LOWSPEC is about a quarter of the cost of an equivalent 'off the shelf' spectroscope, so if you can't justify spending loads of dosh then this is a viable option. Eric.
  3. Thought I'd try something different while my Mammut CCD gets repaired/replaced or refunded. I dug out an old cheapo black + white security camera (ALDI I think) to see if it would be any good for spectra with a Star Analyser 100 (sa100)? I also had a cheap usb capture stick allowing me to record spectra as videos to my laptop. The security camera chip is a tiny 1/4" so it took a while to align. Luckily the camera has a Toucam type thread so I had no issues mounting it to the telescope. The video capture control was just limited to brightness + contrast, but I managed to turn it down a bit to avoid saturation. The 30s of video was stacked in Registax6. Below are Vega spectra taken (on different nights) using different setups, (including a DIY slit spectrometer), but all on the same 8" F5 newtonian telescope. Conclusions? The resolution of the 300 l/mm slit spectrometer resolves elements not visible on a slitless sa100 setup, (Ok that was obvious!). QHY5 has the best UV response The multiple lens elements, (50mm + 135mm DSLR lenses) or the grating, in the 300 l/mm slit spectrometer seem to degrade the UV/blue sensitivity compared with slitless sa100 Mammut. (I might try just using a simple doublet as the colimator when I rebuild it). When you consider the price (£10?), the security camera hasn't done that badly. The hydrogen balmer lines are clearly visible. I am not suggesting you ditch your CCDs and go for a security camera (as there are other factors that come into play). What this does show is that that you can start spectroscopy with whatever you have to hand. I want to try Vega with a Phillips 880 webcam next to see if the security cam beats the Phillips web cam because it doesn't have a bayer matrix? Place your bets now! Thanks for looking John
  4. Somehow managed to get some shots of the supernova in M82 last night despite the best efforts of the clouds. Needed to use 2x2 binning as there was no opportunity for longer exposures. I know nothing of supernova spectra, apparently the big absorption dip is Silicon. Thanks for looking John
  5. I think have ironed out a few more niggles with the latest DIY spectrometer. Replacing the 50mm SLR collimating lens with a Paul Rini 0.63 focal reducer has upped the resolution nicely. Here are 3 Be star spectra captured on the 11th Jan. 10 Cas was quite challenging and needed 2x2 binning due to the low SNR. Thanks for looking John
  6. The animation below has 6 days of image stacks of the M82 supernova, (alas not concurrent nor evenly spaced days thanks to the appalling weather!). Each profile was scaled relative to a nearby star. It is sufficient to show the nova brightening up to the 2nd Feb and then dimming down. There are spectral changes too, especially between 500 to 550 nm. A high level summary of what's actually going on would be most welcome. Here is a non animation version Thanks for looking John
  7. My first image of B]etelgeuse and Bellatrix, early hours of Saturday morning. I think it was still a little low for a good observation, but some interesting lines. Kate
  8. My first attempt at Uranus. It has been corrected for instrument response, but I ran out of time (due to mist) to image a G type star, so divided the image by the G2v reference image in rspec instead to correct for sunlight. Think it looks okay. Have posted both the corrected and the normalised images. Kate
  9. Here is a link to a short video of me demonstrating the L200. Video taken by Thierry Garrel - so I blame him for this ;0) Enjoy.... http://gabalou.canalblog.com/archives/2012/07/14/24703754.html
  10. Conditions have improved allowing use of the slit spectrometer. Here's a comparison of the same target, same evening, taken with the sa100. The sodium dip is evident. Using a long transmission spectrometer without a flip mirror is a PITA on dim targets. If anyone has a spare 300 l/mm reflection grating then please let me know! The chart below shows 4 days worth of sa100 spectra. Again I have done a quick scaling adjustment relative to a nearby star to get a meaningful indication of how the supernova is brightening. The most recent profile has picked up the sodium dip. Thanks for looking John
  11. Hi Folks, Been quite a while so thought I post up some Beta Lyrae (Shelyak) spectra when I managed to take advantage of several clear nights in succession at the end of July. There is too much data to show, so here's an animation showing Hydrogen Alpha and Helium (6678 A) over 10 nights spanning 2 weeks. The next images show an analysis of the Si line to measure radial velocity, (Shelyak is a binary system). The image strips show the Si lines moving relative to the static telluric water line at 6516. Finally here is the chart of radial velocity over time. (Heliocentric correction has not been applied). Thanks for looking John
  12. I know that astrophotographers can use diffraction gratings and filters to image a star's spectra. However, is there a filter or eyepiece that a visual observer can use to see a star's spectra? Like, look through an eyepiece and instead of seeing points of light you see each star's spectra? Or am I going stir crazy from a lack of observing ?
  13. Hi all, Took images of these the other night, very peculiar looking. Does anyone have a spectra I could compare to mine. Will post once I have checked again. Kate
  14. Hello, I would like to try and work on some double stars with my star analyser. I have tried, but seem to have a problem collecting data for the dimmer star. When I collect the spectra the brighter star seems to blot out the second star and I get very limited data. Is this because I am using a 5 inch scope which obviously shows widefield and therefore not enough distance between the stars, or is there something else I can do to improve the dimmer star. I am also wondering if I took a series of images of a star which has is a spectroscopic binary would I actually be able to discern any difference as one star passes in front of the other with my set up? Kate
  15. Hi all, Anyone out there interested in Be stars. I have been taking spectra of some of these and they have beautiful spectra with great variation between the different stars - depending mainly on whether or not they have a disk or not going round them and also the angle of the disk to us. And the great thing about taking the spectra is you can put them in the BeSS database afterwards where they will probably by used by professional astronomers in their research. You may even get your name mentioned in one of their papers. Anyway here are some spectra of Be stars I took over two nights. Enjoy :0)
  16. Hi, I completed a small 3D printing project yesterday to have a cap for my Star Analyser 100 filter while it is permanently fit on DSLR lenses. Here it is the 3D model if anybody else wants to print such cap for a filter: https://www.thingiverse.com/thing:2834248 Csaba
  17. Hello, Last night I added a focal reducer to the MX916. This is the first test with it included as an extra spacer, next time i will put it at the front of the star analyser so I can compare the two and decide which is the better arrangement. Attached is my image of Regulus, which I knew was a B class star so was very amazed to see a spectra which looked so much like an A class star. I also looked at a couple of HIP stars around regulus as i was trying to work out the extent of magnitude I could easily image. One of them HIP 55262 is near M65 and M66 which I ended up with a spectra of. Can I calibrate these as I would a star or do they need different treatment? Is there anything in particular element wise, I should be seeing? Kate
  18. Hello all, not at all sure if i got this right, but managed a set of images of the comet with my 5 inch and the star analyser. I took 50 30 second images and stacked them. The comet was on the way down, so it looks a little noisy. After calibration I divided by instrument response and then subtracted a close G type star (to account for sunlight - not sure if I had to do that) Is it close, if not how can I improve it or is there just too much noise? Kate
  19. Hello, I am using a 5 inch Mak-cas telescope with my starlight MX9 and a star analyser to take spectra. Recently I added an extra spacer which has improved my data collection. I am now wondering would it be useful or not to use a focal reducer or would this either make the image too small in my scope or move it too far away from the chip? I have attached my recent images of Alhena, Mebsuta and Mekbuda Kate
  20. Star Analyser 100 in pristine condition + spacer (to give correct spacing with CCD chips). Details (including a calculator to enable you to determine whether it is suitable for your system): http://www.patonhawksley.co.uk/staranalyser.html Reason for sale: I have upgraded. £80 (Normally retails for £105.71 + P&P), includes GB insured p&p. Bank transfer preferred; PayPal (net of fees) accepted. Advertised elsewhere.
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