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About Howie_Oz

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  1. Disclaimer .... My fav cams for use as EEVA are actually Canon DSLR's combined with AstroToaster. With 7 years of experience using them, I reckon 4 frames of 15 sec at ISO1600 with your modded Canon 450D would easily get M27 (and have better detail and with nice sharp pinpoint stars) when used with AstroToaster out in the field at night next to the scope. I've done M27 with single 15 second at a dark site using Canon 650d and AstroToaster. BTW Your Sony Alpha may be even better with it's higher ISO's ... but the Sony's dont lend themselves as easily to in-the-field EEVA processing and stacking. Sony's need both a remote to control the camera exposure and ISO and intervalometer and also need a wifi SanDisk card to send images wirelessly to a laptop folder where you can tell AstroToaster to auto find and stretch them etc. But it is doable using a Sony ... just a bit of faffing around. However, you're chasing REALLY sensitive cam! OK ......... lets get onto that! The ZWO ASI224 has been regarded for several years as being very sensitive and so has been one of the most highly regarded cams for EEVA. The ASI183 also is sensitive and well regarded for very short EEVA. Both have small sensors and so will magnify heaps on any scope they are put onto. TIP: A 5mm sensor will produce a FOV like a 5mm Eyepiece on any particular scope. A 23mm sensor will produce a FOV like a 23mm EP. And so on. However, a small sensor is better for EEVA (IMHO) as they will work with most reducers (even heavy reduction) without vignetting, and this has a HUGE benefit ... it reduces the F ratio for the camera. This lower F ratio allows much faster exposures compared to using them unreduced. And for AltAz you need very short exposures! It's a testiment to especially the ASI224 but also to the ASI120 and ASI183 cameras that I've owned, that when I've sold them for one reason or another, I've ended up repurchasing another one to replace them down the track! LOL. I keep rebuying (especially) the 224, as I find more and more uses. Such as .... I am using my Star Adventurer and camera lens for REALLY widefield with them. They also (due to the sensitivity) make EXCELLENT e-finderscopes! If you load ASCOM and platesolving then you actually dont need a finderscope at all ... find target in stellarium, click to slew to it, then tell Sharpcap to platesolve using the main OTA cam and to slew from there to your target object and if it wasn't centered (or even in the FOV) then it will make the correction based on the platesolve and slew to it correctly. But ... when starting out you dont need to load all this stuff! I'm just giving you reasons why despite me favouring DSLR's for very good EEVA, I still buy very sensitive ASI cams for all the reasons in this paragraph. BTW most times I dont bother with platesolving anyway ... I run an ASI224 with a 55mm Canon lens as an e-finder and centre using it ... as it will show colour and faint stuff very quickly. Once centered I setup the DSLR in the main OTA confident it is then centered. This method allows me to use the very sensitive 224 e-finder to do my Skywatcher mounts star alignment and PA. Or (back when I had one, my Nexstar mounts alignments). Anyhow .... here's a link to a video down below showing a bloke using the ASI224 live ... does couple of globs first then moves to M57, and M27 ... you'll see the stars slew past as he slews to the objects and even when framing the object with the movement buttons you'll see it is live. His M27 is 4 second exposure! OK at 4 second for one exposure it is missing details .... but key to using that sensitivity is the software he is using (SharpCap) allows stacking. He doesnt show it, but when you can see a half decent single exposure image (like his 4 second M27) then how you stack is you click the Stacking button visible in that video on the top menu bar of that software and sit back watching the image get better and better. All while out there in the field next to the scope. Or as many do, with wifi and long cables sit inside in the warmth controlling the scope and cam outside. Or, down-under where I'm from, sitting inside in AC and away from the insects. Link to video is ... https://www.youtube.com/watch?v=O6n2z6rj_98 And this next one he is operating at F2 using hyperstar reducer so just 1 sec frames .... https://www.youtube.com/watch?v=iTgVT_WGThM
  2. Extremely nice shots Steve! Thanks, as I've been looking at the combo of 294mc pro and tri-filter for a while. Sorry, as I might have missed it in the first post, but what (Bortle etc) skies were you in?
  3. Great result ... makes me want to get the old Mallincam VSS+ out again! One question ... what is AS!3 ???
  4. Decisions, decisions! LOL. And .... if you raised the OBS one or even two metres off the ground all the above would change again! LOL All the best mate. Can't wait to see where you decide. Post up photos as you build ... cheers
  5. Thank you Martin for all your work doing that. Interesting read too that PointSources pdf.
  6. Great vid. Thanks for posting.
  7. Out of all those specs Martin, how does one work out the sensitivity for one vs another camera? It's often stated to use a "more sensitive" camera if on Alt Az for instance, due the shorter exposure times due field rotation effects. So sure with a less sensitive camera/sensor you can just stack more and eventually get nice bright(er) image. But you have to wait longer for the stack as you are doing more. But if doing outreach, or 'true' VA (not really caring too much for quality and just want to see lots of stuff during the night) then you want something more sensitive (so you don't have to stack much to 'see'). So, can you work out 'sensitivity' for those cameras from the info in the table?
  8. There's probably some smart way to calculate it all. But being not smart enough for that, I made up a jig. Imagine a plank of wood on top of two saw-horses down by the bay near where I live. The whole xx12 tube lay on top horizonally and pointing across the bay towards the port facility on the other side of the bay about 5 km away. The camera was inserted into the focuser (along with its 2" Baader MPCC Canon fitment) and (importantly) with the focuser wound out about a two centimeters to allow for any possible adjustment around the focus point later on. But ... the Orion struts were not holding the primary and secondary tube assemblies apart on that "jig"! The primary and secondary tube assemblies were resting in a 'bay' created by two lengths of straight timber screwed onto the plank. Thus gravity held the primary and secondary tube assemblies hard against the horizontal plank/timber guides, which being straight still held the optical alignment between primary and secondary mirror cells. I simply moved the secondary mirror assembly containing the focuser/camera slowly towards the primary cell until I got focus. Then I measured the distance between primary and secondary assemblies. Back home I reassembled the xx12gt using the proper struts and checked that measurement to find I needed to drill those second holes exactly 40mm towards the primary mirror to work for my Canon 700D. So the four attachment plates on the struts where the struts attach to the secondary mirror cell, needed a second hole drilled 40mm closer to the end pointing to the primary mirror. I took the struts to a local machine shop where they had proper drill presses, to guarantee each hole was the same distance from, but still aligned with the centre of the original holes. They were so intrigued with it all, and in disbelief that an amateur telescope could be THAT big, that they didn't even charge me for it! LOL. Note that it was not required to perfectly optically align the primary and secondary cells in the "bay" on the plank. As long as the camera showed focus, and the focuser knobs allowed me to wind up to then past the point where the camera got the best focus on that 'rig', that's all that was needed. For once the struts were drilled mm perfect at the machine shop, and I then did a collimation, the focuser would look after that last absolute perfect slight adjustment to bring it properly to focus out there in the dark. Leastwise, it worked out well for me. Cheers
  9. I've got the same GoTo DOB as you ... XX12GT. I drilled a second hole in the strut secondary are as per the photo's ... brings my Canon DSLR APS/C camera to focus nicely. If I used EP's init to do alignment or visual I simply stick a small 2" extension tube in and EP's will also then come to focus. EAA with the APS/C sized sensor worked a treat with EOS Utilities controlling camera ISO and exposure times. Setup EOS Utilities to save images to a folder monitored by Astrotoaster on a bootcamped Macbook. Astrotoaster uses DSS in the background to do the stacking (if necessary) and Toaster to do the AP-like stretches so it made the EAA image happen. None of my EAA shots from that DOB available unfortunately, as when Photobucket went to a cash-to-use model I declined. And those buggers simply wiped the account photos and all. However, my example inspired a friend of mine in New Zealand to do the same. Link to his shots below using DSLR on Skywatcher DOB for years with all sorts of scopes piggyback on it. Being adjustable struts he did not have to drill any holes but simply adjusted the length via the adjustable set-point knobs. He rigged a counterweight system on a adjustable rail so the Alt motor could see the load as balanced ... and so would still work in Alt. He carried ED80 + a second DSLR for widefield, and whole bunch of piggybacked scopes as per the photos of his rig down in the link below. The APS/C sized sensor gives a good 1.2 degree FOV on the 1500mm DOB. A great view of most Messiers. The stacking capability of toaster allows much more SNR in the final stacked image which allows some very good shots from the combo. BTW. You can also get bigger primary mirror bolts to "push" the primary mirror into the OTA more thus pushing the focal point further out the tube (instead of modding the XX12GT struts). My photos showing how I moved the focal point further outside the tube thus allowing the DSLR to come to focus. https://flic.kr/s/aHskZvmNDE Very long video when I first tested that the shortening of my struts had worked nicely. It had reached focus and was amazingly sharp ... live HD desktop capture of Moon surface at Canon EOS Utilities 5x sensor zoom. Dont watch it all as its 15 minutes! https://youtu.be/LQJ9WyE2nmA Friend in NZ showing his amazing balanced DOB using moveable counterweight system ... https://flic.kr/s/aHsksGCqYM His amazing DSLR images using that setup ... https://flic.kr/s/aHskGspbb6
  10. Ditto on everything stash_old says! I've had Samsung SCB2000, various Mallincams, various ZWO's and IMO nothing beats the simplicity and very sharp almost AP results using DSLR on f/5 and lower OTA's. Link to flickr album below ... 3 partial nights viewing using 9 x 60 sec frames ... all screengrabs showing the image on screen in-field at time scope is slewed onto targets and like stash says ... you see the image right from the first frame and then watch it better over the subsequent shots. Usually I set toaster to single shot processing and take single iso12600 frames of around 5 seconds in order to find/frame the object nicely. Then when its framed nicely I set toaster to stack and set the dslr to shoot 9 x iso800 or iso1600 30 to 60 sec exposures. I adjust a few toaster color adjustments and expand gradients after the first shot comes in. Then I sit back for 10 minutes and watch it get better and better with each passing image. https://flic.kr/s/aHsm9Ld4SC
  11. Before accepting anyones advice on which camera, you need to learn how to very quickly and easily check that you don't get caught again with too much, or too little magnification. Cameras behave very differently depending on their sensor diagonal size. They actually behave very similarly to an eyepiece of the same mm rating. Ie a camera like the altair suggested ... check the manufacturer or retailer websites and you'll see the sensor is about 5mm diagonal. It does not have to be exact dimension - near enough is good enough so if they quote the horizontal and vertical dimensions in mm there's no need to get out the calculator and use pythagorus to cal the diagonal to the nearest 2 decimal places ... just use the bigger dimension ie the horizontal one in mm. So the amount of magnification and therefore the field of view or how large or small objects appear for that camera with its 5mm sensor will be very, very similar to using a 5mm eyepiece in any scope you own no matter what its focal length. If you get a suggestion of DSLR you'll look up the sensor dimensions to find thats about 23mm diagonal. So it will yield a very similar FOV, magnification, size of object as using an eyepiece of 23mm in any scope. And so on ... anyone suggests a ZWO ASInnn ... or any camera ... check the sensor dimension specs and you'll immediately get the idea of whether it'll work in one of your scopes. As I suspect you found with your old VA and the large F5 dob ... those old VA cameras had 5mm sensors so would show you the same FOV/mag as using a 5mm highly magnifying eyepiece in your DOB. If that dob was 1500mm focal length then you effectively had a 5mm eyepiece in a 1,500 focal length scope ... very high mag, very small FOV, unable to find stuff when the goto is off, unable to image big stuff. It would, however, been great for planets! Or an alternate method is to google "12dstring fov calc" and go to that online resource. Its a visual checker with 110 Messier objects and all the solar system objects with hundreds of scopes and cameras from hundreds of manufacturers to see if a camera will work with your scope. The only thing it won't tell you is (a) if the camera will reach focus in your scope(s); (b) if the camera will get vignetting in your scope(s); (c) if you can get a reducer to make it work better with your scope(s) - as you can enter barlows and reducer values in that online tool to check planetary vs DSO scale. To get those questions answered once you find a scope and camera and reducer/barlow combo which works ... is to post questions on the forums, or get money back guarantee from the supplier if it doesnt work with your scope. Cheers
  12. Need my old network drive for non-Astro stuff so checked content before deleting. Found this old late 2016 HD desktop capture from very dark site ... town of Leyburn 3 hours from Brisbane. Single 15 second frames with the DSLR in order to avoid the wind bouncing the scope too much. Nearly all are low hanging bright objects, however the last two objects weren't quite "low hanging fruit" being the western and eastern veil. These were single 30 second frames. Its a 28 minute vid as I blab on as usual, but its live ... no gaps. It includes selecting the target, punching it in the hand control, the slew time, the 15 second shutter and then finally see the image in astrotoaster. Still manage to do 15 objects in that 28 minutes though. So still very fast acquisition. Speed the video up to 2x normal (a) to shorten it a bit and (b) to hear me sound like Donald Duck!
  13. I cannot find the thread, but ages back I saw someone having similar issues with wifi. So they ran a power cord from inside to outside OBS, and ran EOP (ethernet over power). Fixed up all the problems. Apparently Of course if you are portable setup then it won't help out in the field.
  14. Ooooo .... aberations ... you may get vignetting with such big reduction and a mid sized sensor in the Infinity. But get out and try it out. You did good in getting 2nd hand (and those 0.3x SCT reducers are scarce as)! Do hope I didn't confuse you there? Bottom line ... crack on with the Infinity and 0.33x test. Crop off the vignette if you have to and see if it works for your needs. If not, resale should not loose you money. If you decide to keep the 0.33x anyway for future use ... it'll work nice with smaller sensor cams of around 5 to 6mm diagonals. Don't read the rest of this post ..... Unless you'd like to know why diff sensors may or may not vignette with reduction. It's not a physics explanation with precise correct terms etc, but it's how I think of it in an easy to remember way. When light is focused by lens or mirrors, it forms a cone of light. Light intensity/brightness is brighter in the middle of the cone of light, and falls off at the edges of the cone. Hence a small sensor does not extend much into the edges of the poorer brightness of the cone. So they suffer much less from vignetting (dark corners and edges). Larger sensors extend much more into the less bright edges of the cone of light, and so suffer much more from vignetting. The larger the sensor diagonal the more it suffers from vignetting. Second handy thing to know, is reducers act by steepening the angles of the edges of the light cone (so they "reduce" the focal length of the scope). It is this steepening of the light which stretches the stars into elongated rather than round (IE coma). The middle parts of the light cone are still relatively unsteepened as the light right through the middle would clearly be still parallel coming straight down the middle of the scope, even though the edges are now more steep and stretched in order to reach focus shorter than without the reducer. So once again, small sensors will sit more in the region which is less stretched and are less likely to get coma. ANd I'm sure you can then work out why the larger the sensor the more it gets coma around the edges. And third thing to know, Is because reducers (effectively) shorten the focal length of your scope, it means the point you reach focus moves further and further into the scope as you add more and more reduction. So to work with reducers, your scope needs lots of focuser "in-travel". Refractors and SCT's have much more in-travel so usually (not always, but usually) will have enough travel into the scope to bring the camera to focus. However, if you ever think about getting a Newtonian telescope, they do not have much in-travel in the focuser and often cannot bring a camera to focus when you use reducers. People desperate to use reducers with Newts often resort to shortening the tube with hacksaw, or replace the primary mirror bolts with longer ones so the mirror is moved into the tube, or shorten the struts (if its a truss newt - and its what I've done to mine).
  15. Ditto to the comments above. And the kit you have chosen was wisely chosen for starting EAA. Your review and experience should be a sticky thread on SGL under the EAA / VA under "Example of how to correctly get started in EAA"! Great to see an excited new member of the "Observing-With-Camera" club, especially the shots of what you saw. Top write up.
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