SA200 group purchase

Sounds great, thank you for giving us this oportunity.  I am in!!  Just tell me what to do next.

Frank

I would like to buy one also.

Thanks,

Blake

I want an SA200 too.  Let me know how to order and pay.

John Centala

Thanks Arne!

I'll take one. Tell me when and where to send the money.

..george

I'm in

Hi Arne,

The SA200 is on my wish list. Looking at the normal price online $160US is a very good deal. My current camera set up is an SBIG ST-7 and CFW8A fitlerwheel. I've found diagrams of all the equipment with back focus distances and run the results through the r-spec grating calculator - turns out I could do either grating and each would have some advantage or disadvantage. However, if I get a camera with a larger chip in the future (back focus remaining similar), the principle difficulty highlighted by the grating calculator goes away... so I'm thinking SA200.

Its hard to imagine that shipping to New Zealand could add that much more to the price. NZ Post operate a postal forwarding service that offers very competitive rates so that would leave the AAVSO having to send to a US address, and I'd take care of the rest via the forwarding service.

When are you going to take delivery and when do you want the money?

- Carl Knight (KCD)

Arne,

I'd be interested in purchasing a S200 too.  Is there a kit to mount them in a 50mm SBIG filter wheel?

Thanks,

Frank

What is the process in order to aquire one!

thank you for the information

JAC

Hi Arne,

I am interested in picking up one of each (an SA-100 and an SA-200).  Please let me know where to send what I owe.  This is a great (grate?) opportunity.

Neil

We have enough interested people that the group purchase will happen.  I'll give other readers a few days to make their decision, and then will close this group purchase early next week.  I'll then get a final price from Hawksley (including shipping, credit card costs, currency exchange rates, etc.), and put this figure on the on-line store, and ask everyone to purchase a grating from us.  At the same time, I'll send the group order to Hawksley, and when the gratings come in, I'll distribute them to the purchasers.

There is a place-holder on the online store now; I ask that you do NOT purchase until I have a final cost (which should be very close to the original estimate, but might be a few dollars more or less).

For the diffraction gratings, my expectation is that we will store full images on the website rather than extracted spectra.  For other spectrographs, we may archive differently.  This is a multi-faceted project, so I decided that the first step would be to get a few of the gratings into observer's hands for experimentation while we get the software and archival process finalized.

Arne

Please include me for one (1) SA200 grating and advise on when and how to make payment.

Thanks.

Gil

I hope that John Martin is getting a commission for the workshop on this in Woburn!

...Tim

Hi all,

Just to say that although this may be a new field  to some of you, the Star Analyser has been around almost 10 years now with over 2000 users worldwide so there is a lot of user experience with it out there.

I do not routinely monitor this forum but as the developer of the Star Analyser I am happy to answer any technical queries you might have about it on the staranalyser yahoo group.

https://groups.yahoo.com/neo/groups/staranalyser

You can also find more in depth information on the SA200 on my website at 

http://www.threehillsobservatory.co.uk/astro/spectroscopy_16.htm

and of course dont forget to RTFM ;-)

http://www.patonhawksley.co.uk/resources.html

Looking forward to seeing your results!

Robin

Thanks, Arne!

Please count me in, too, for the SA-200!

Cheers,

Helmar (AHM)

P.S.: Do I understand correctly that there will be a "placeholder" on the AAVSO Store (there is none, yet), but we should wait with purchasing until you confirm the group price on this forum?

Count me in.

thanks

Paul (BPAD)

Hi, Arne,

Not to digress, but I am wondering if anyone has used a diffraction grating in conjunction with a DSLR from which the Bayer array has been removed?  I have a T-adapter for my camera and telescope that allows for a 48 mm filter (nominally a clear filter for dust protection) and wonder if I could do anything useful with a diffraction grating. (The camera - filter arrangement is placed at prime focus.)

My principal interest is in CVs, and I've learned that useful photometry of these stars just isn't possible with a straight DSLR.

Cheers,

Stephen

good afternoon  Arne

The group purchase only applies to US Citizens! this is correct?

Weel a foreign citizen would need to provide shipping delivery to is Country, Aassuming that he/she would be eligible! if this is also correct! then the foreign citizen just needs to work with  AAVSO for these type of transaction.

Kind regards Arne if you can clarify this.

JAC

Any possibility of doing a group purchase for the software--I think its called SPEC.  I think any software can be used.

Gary

Hi Arne,

Put me down for a SA200 as part of the AAVSO group purchase.

Thanks,

- Carl

I want an SA200 too.  Let me know how to order and pay...

I live in Quebec, Canada and I will be interested depending on the price.

I

Hi!

Can you count me on this group interested to this group purchase?

I'm new but I'm very interested on it.
Thank in advance!

JBD

I would be interested in getting an SA200.  Let me know how you would like me to pony up.

Thanks for arranging!

Marshall

There are many freeware programs which can be used to process spectral images into profiles (1D fits)

ISIS

http://www.astrosurf.com/buil/isis/isis_en.htm

VSpec

http://www.astrosurf.com/vdesnoux/

BASS

https://uk.groups.yahoo.com/neo/groups/astrobodger/info

Hi Arne,

you can count me in ("me", that's Andromeda, the Astronomical Society of the Dender Valley" (Belgium)). I'll mail you an address in the US (Washington DC) where the SA200 could be send to. Thanks!

Bart

I will take the plunge

Gary

Paton Hawksley will give me the same discount on the 50mm adapter kits, so those will also be available in the online store when I make the group purchase.  You can also order either the SA100 or the SA200, or both, Hawksley is giving me the same percentage discount; the SA100 is a bit cheaper, but does not work effectively in a filter wheel.  Foreign orders are ok, but there will be an extra charge for postage and handling.  These are small items, so we should be able to ship via regular mail, but I won't know those final costs until next week at the earliest.

Keep the pledges coming!  I'll see if they will give us a better discount when I order, since we are over the initial group volume hurdle.  I am not trying to make the AAVSO a distributor for Paton Hawksley, just doing the initial "seed" to get the group going.

My intent is to provide some basic projects for grating users.  Some will be purely experimental (can we do spectrophotometry?); some will be monitoring; some will be waiting for targets of opportunity.  As mentioned before, several AAVSOnet telescopes have SA200 gratings now, so we'll highlight those on the AAVSOnet page and accept spectral proposals.  A simple method of saving and retrieving images will be developed as a placeholder for a more complete spectral database.

Arne

If you are wondering which to go for (SA100 or SA200) then you might find  the information  here useful

http://www.threehillsobservatory.co.uk/astro/spectroscopy_16.htm#SA200_…

Put simply if you have the space in your imaging train to get the spectrum long enough then the SA100 will marginally outperform the SA200 for the same length of spectrum. ie more (lines) is not always better in this simple configuration.  If you have to mount the grating close to the camera though (eg in a close coupled filter wheel) then the SA200 is the one to go for. Also as it is slimmer than the SA100, it is more likely to fit in your filter wheel.

Note that the spectrum resolution is highly dependent on star image size so if you are looking for best resolution then a tight star image is key (ie smaller apertures in good seeing give the best resolution)

Cheers

Robin

I'll pledge to buy one.

Ken

Appreciate the opportunity -- please count me in as well

Dave

I'll sign on for an SA200 - that seems like a better fit for my ST-9 and filter wheel.

Shawn (DKS)

Please put my name on this list also. I'd love to have one. Thank you.

I'm definitely feeling  a sense of Déjà vu here.  It takes me back to the days leading up to the Star Analyser. Back in 2004, I distributed about 50 gratings that I found in a French educational supplies catalogue to members of the webcam modifiers group (QCUIAG) around the world.

https://groups.yahoo.com/neo/groups/QCUIAG/conversations/messages/77479

It was a few months later that I found out that they were manufactured by Paton Hawksley here in the UK so I paid them a visit and asked  if they could supply a better  quality version and mount one up in a 1.25 inch cell for me. I persuaded them that perhaps  other amateur astronomers might be interested and the rest is history as they say. I hope you get as much fun out of the Star Analyser  as I did

Robin

Thanks, Robin, for that visit to the past!  I remember those early days of the spectrum analyzer.  I am both an enthusiast as well as a scientist, and see the SA200 as a good entry point into spectroscopy for a wide range of amateurs.  It is fun, as you mention, to see spectral features spread out from that point of light, or as John Martin showed, what happens when you image a planetary nebula.  At the same time, I want to push the envelope some and see just what science we can get out of the devices.  I was impressed to be able to get reasonable spectra from the Bright Star Monitors.  I'm willing to bet that there are several parameter spaces where diffraction gratings will be useful.  Classification of galactic transients.  Classification of supernovae (as John showed).  Monitoring of emission line objects.  Rapid response for transients (since there are potentially many more of these than spectrographs); perhaps even spectra of the prompt gamma-ray afterglow emission.  Simultaneous BVRI photometry of objects.  Then, there are a whole range of educational projects that might get people interested in science, in stars, and even in variable stars.

Let's see what happens.  I'll work on providing the infrastructure first (at least over the next two months!).

Arne

I'd like to buy one as well.  But I'm not sure whether to go with the SA100 or SA200.  I have a 12" LX-200 with a 2" IFW in front of an AP-7.  I haven't decided whether I'd like to pull a filter out of the current BVRcIcC set and put it in the filter wheel, or pull the filter wheel when I want to use it and mount it to the nosepiece of the camera with extra spacers.  I understand the limiting magnitude is a little better with the SA100.  It would be more trouble to have to pull the IFW to mount the SA100 onto the nosepiece with extra spacers to make the 100 work, but if that gives better limiting magnitude and ultimate performance, then I might go that way.

I have not been able to find the depth of the CCD chip in the AP-7 so that I can get accurate numbers out of the online SA100/200 calculator.  Does anyone know that number by any chance?

Clearest skies,

Walt

Arne

Put me on the list for an SA 100.  Let me know the particulars

Mike Miller  MMGA

Hi Walt,

I don't know the answer to the depth, but you can determine it empirically.  Look for dust donuts from the entrance window, measure their physical size on the detector, and use your f/ratio to determine the distance.

Let me know whether you decide to go with the SA100 or SA200.  Robin indicates there will be little difference in limiting magnitude.

Arne

Hi Walt,

I have just checked out the AP-7  (512x 24um pixels ?)  With these big pixels f10 is ok but you will need quite a large distance to the grating to get good dispersion so I would recommend the SA200 on the nosepiece with spacers (or extension tube) to bring the distance up to 60-80mm or in the filter wheel provided you have at least 50 mm spacing there. 

Cheers

Robin