Just to be consistent and we can compare results: Two photographs of the same object made with an OTA of 8". One is taken with a Newton Quattro + IMX224 and the other with an RC 8" + IMX294.
The IMX224 gives a little more detail with less exposure than the IMX294. Influences FOV, pixel size and sensitivity to light in the result, among other things.
This type of objects ( small gx+globulars+P nebulae) are almost 70% of the objects that we can photograph in the sky so the combination Newton + IMX224 must be taken into account to get good results, IMO.
The newton and the IMX224 are low-cost materials that are useful even for advanced amateurs.
The amount of images stacked and the difference in detail of the final result warn that for this type of short exposures very large stacks do not improve the final result (that was already explained on the Starizona website but many forget it)
Nice. But you are on two different scopes ... different F ratio's, as well as 18" with one camera and 30" with the other, and probably different gain on both cameras as well?
Your skies are fantastic over there ... if you can get out again soon, can you just use one scope (the quattro) and both cameras. Then there is no optical difference.
As the 294 will have wider FOV than the 224. Crop/zoom in on the 294 image to get the same image scale/FOV as the 224.
Single frame (no stacking).
Put 224 in first and adjust exposure time and gain to get the best single frame image of the object. Best brightness and detail (although single frame will show noise). Save the 224 shot from sharpcap.
Put 294 in next and adjust exposure time and gain to get the best single frame image of the object. as above with the 224.
Then we'd see the same object image with similar/best brightness and detail from the same scope at the same image scale ..... but we'd notice that the 224 may be gain AAA and BB" exposure, while the 294 was gain DDD and EE" exposure. And we'd see the noise from both as they are single shots.
I'd LOVE to see the result Elpajare! I've been looking at the 294 for some time. My back injury is healing and getting a hankering for getting out doing EAA again. I love my DSLR APS/C sensor. A friend of mine also loved his DSLR, but has just got the 294 and his images are much, much better than he ever got using his DSLR. So I am very interested in the 294. And as I have used the 224 (still have one in my pile of equipment !) I know what I can shoot with that, so your comparison 224 to 294 would tell me a lot about the 294.
No problem elpajare. I'll have to ring my friend with the 294 and try to borrow it off him. Won't be any astronomy here for a while though as we have a cyclone heading our way. Should be here on the weekend. The Moon is at perigee (closest) so the high tides are the highest for the year and will be even higher because of the cyclonic storm surge on top of those high tides. I'll have to emigrate to Spain and join you in those great skies you have!
It is clear skies down south Howie. I was going to get a couple of images with the 224 and 294 on the 200 f/4 newt tonight, not to prove anything,just to compare my best efforts for each camera. I got off to a bad start trying a 1 star align for the first time on the synscan and things deteriorated from there. I accidently jarred my wrist and packed it in. I will try again tomorrow night .
Our winters are cloudy Carlos . We get a lot of clear skies for the next few months in Spring. At the rate you photograph, you would have the Southern skies covered in no time. cheers Paul
Carlos It is a bit of a sequence of events that may be a bit boring. From the previous session, I hibernate the scope to home and then turn off the mount. Next session , I start up synscan. If I didnt disconnect the mount from synscan on the ipad , it gets everything 90 degrees out .It thinks home is the mount facing south but the scope is east -west. Dont ask me why ,but it does. Last night I did a one star align on Achernar and the scope headed in the wrong direction. I jumped up in the pod to stop the scope and hit my wrist which is in a new splint after removal from the plaster cast and everything went belly up from there. There is another bug in the synscan program. If I plug in say M42 and hit return on the keypad, the whole synscan program and ipad freezes and I have to reboot the ipad . To avoid this ,I simply press goto and there is no problem.That was consistent on 2 ipads and 2 wifi's. Not sure if that is still happening because I make sure I dont hit return. Have you gone to sleep yet?
Tonight looks like it will be clear. I will perform a polar align then a 2 star align and try the 1 star align on another night. cheers Paul
The difference with me is that I do not use a smartphone to control the mount but a PC.
I do not have this kind of mistakes.
My work flow is this
I park the mount every night at Park position I turn on the command and tell him that I do not want to start from the Park position I put the day, hour and saving data light time, etc.. I choose alignment to a ONE star I choose the brightest star and next to the objective I center the star from the PC / Skysafari and pulse done
To fine-tune the location I use the Re-align option of Skysafari with a bright star next to the object
I put a picture of my installation, the shed with the PC is small but comfortable at night. I have replaced the tripod with a pillar.
TSOptics Ritchey-Chretien 203/1624 for small and weak objects
Tsoptics refractor AP 72/432 (fpl53) for big bright nebulae and other big objects
Thanks Carlos I am happy enough with the ipad. The synscan software has a few glitches,but I am slowly working them out. Tonight I will start again and polar align and 2 star align on the EQ6 but will try your method next time as it sits in a skyshed pod and doesnt get moved. I think Ken doesn't even do a 1 star align in his shed. He turns synscan on and immediately goes to the DSO and finds it very accurate.I will eventually work it out.
I like your pier. I have a HEQ5 which I have to polar align every time because I move it into a shed every time I pack up. cheers Paul
Yeah Paul, move the mount everytime and like me you'll have to always do 2 star then PA then 2 star ... put on a pier, or dont move the mount, and remember to always park it at end of viewing, and you can power up and answer date and time accurately and you can go for it without need for alignment ... but only if and only if you enter the stuff accurately.
It's because the mount has a perfect star map in its 'brain' as soon as it knows the lat, long, date and time. That perfect map in its 'brain' assumes the RA axle is pointing exactly at the celestial pole and that the tube is perfectly parallel to that axle in both RA and DEC (which if you did a Park last time you shutdown ... it is). But like I said, the timestamp has to be accurate. If you are a bit off in the time, then obviously the map in its 'brain' is going to be a bit off in RA and so the go-to will be off slightly.
I still havent had any good weather to do my promise of making a video on setting up and PA etc ... and now it looks like a week of bad weather due to cyclone Oma. I'll get to it one day, or night! I think it will be interesting, as you really don't have to level an EQ mount at all if you put a couple of tricks into play. And another option is simply leveling across the non polar legs leaving the pole legs at any non-level angle ... works fine too. The one I really like for portable setup is the iterative procedure. Now that's a clever one ... so not mine. LOL. But I'll show them when the weather clears up.
Sorry to hear about your probs with the iPad version of control.
Howie, with the synscan I hibernate to home, and turn off the synscan wifi. The ipad then automatically connects to my home wifi. If I dont manually disconnect on the synscan software as well ,then next time I turn on the synscan, it will take me exactly 90 degrees out in dec ??. It has taken me a while to sort out what the bugs were ,but it didnt miss a beat tonight. I got an image of ngc 1365 on both the 224 and 294 on the 200 newt .I will post them tomorrow. cheers Paul
Howie, in spite of having a fixed pier to the mount when removing and putting the tube every night ( every night I take off the tube and I put it in a special container behind the shed ) or changing a telescope for another one always remains something out of tune and I prefer to align to 1 star always to avoid problems.
The truth is that I have never dared to leave from the park position because of what I tell you.
In addition, aligning 1 star is very fast so this system works well for me but each one chooses the best one for oneself. The good thing is to share different ways of seeing things.
Yes, elpajare, if you take the tube off the mount on the pier, then DEC and RA will be affected. Especially if you release the clutches and rebalance when you stick the tube back on. Taking the tube off and rebalancing ... you will never be able to return it to the true previously parked Home position. But, yes, a one star is all it needs to realign it when you do get it back onto the mount in that case.
Not sure why the 224 image is so light. The image on the screen at the time appeared dark. Any advice? Anyway 200 f/4 newt, ngc 1365 45"x4 on 224 and 294. I wasnt trying to prove anything. Best image I could do for each . For your information.
In my opinion the two photos are very overexposed. Look at the peak of the Histogram.
I think it was Ken ( do you remember? can you recover this post?), a few years ago, who said that the peak should be shortly after starting the scale, to the left at no more than 30%. I remember that I was starting then and his article taught me a lot, thank you Ken.
With the 200mm I do not exceed 18 "with the IMX224 and 20" with the IMX294 with the Gain to the maximum and dark skies. You have served 45 "!
Try adjusting the exposure to the Histogram peak and leaving all parameters by default except White Balance
PD: Interesting the Histogram peak for each chip. Confirms the theory that 224 is more sensitive than 294 with equal exposure
Thanks Carlos I need helpful hints like that. The 224 histogram was certainly way over to the right but appeared really dark on screen. When I turn up the gain to over 300 on sharpcap, everything then appears overexposed. I am about to boot up very soon.I will take your advice and see if I can come up with something better.
I will also see how well synscan does a goto without an alignment. cheers Paul
I see what you mean Carlos. What I forgot to mention is that I have a 0.6 fr added in as well. That would account for the total whiteout when I put the gain on max and also the overexposure at 18 secs. I will try again tomorrow cheers Paul