chiltonstar

Nice detail in the GRS (the "Eye").

Chris

Many thanks for the above very useful info and suggestions. Maybe I can persuade The Cat to buy me the TV 8mm for Xmas - after all I've just had to pay for her to visit the vet after she dined out on after sell-by date mouse!

Chris

There was a mini-review of these in October's AN, and although labelled as orthos, they seem to be symmetrical Plossls. Oddly, on the FLO website they come under Takahashi (really?).

Anyone any idea of how well they perform?

Why oh why isn't there a half decent 8mm ortho available? It is a good fl for my 180 Mak and although I have a BST 8mm, it is not up to ortho standards.

Chris

Very nice for the first image! As you say a very different type of skill required cpd with DSO imaging - getting the planet onto the camera chip can be quite a challenge sometimes!

Chris

Interesting topic! They do look quite different through a 4" and certainly through my 180 Mak. I had always put this down to the fact that the Airy disk is not "flat-topped" but a pseudo parabola (ie with a "point") and therefore resolution on some objects can be apparently slightly better than theory (one point Nik, shouldn't the Airy disk diameter and the apparent moon diameter be added as the SQRT of the sum of the squares rather than linearly?).

Differences in brightness will change the apparent visual diameter as well I believe - look at how large a bright star appears to be cpd with eg a mag 8 star.

Chris

On 12/09/2021 at 07:17, Pete Presland said:

Nicely captured, good to see the Mak180 planet killer" still deliver some fine images.

...it would do a lot better if we had more nights with fine seeing! This is the entire 20 sequence above (I selected 6 for derotation) as an animated .gif. You can certainly see the minute by minute variation in seeing!

Chris

Superb report John. I don't know Dartmoor very well, but it certainly matches my experience of a couple of very dark spots in Cornwall we've stayed in.

Such a shame that our children and grandchildren will never have this experience unless we do something serious about LP.

Chris

A very nice Saturn!

Chris

Jupiter last light with a little scope (180 Mak). Average seeing with some better spots. Image stacked in AS, then PS and derotated. Bloody tawny owl kept on making low passes and hooting.

Chris

2 hours ago, neil phillips said:

Been there done that Chris. I feel your pain. It consistently has done that to me too. Not last night was a exception. As i said to Simon. Dont give up Chris. Still time. Hope you get some joy soon. 

Well, I've been an amateur astronomer for 50+ years, and the ghastly climate hasn't put me off yet! I used to keep an Excel spreadsheet of noteworthy astro happenings and I reckon rain/cloud stopped play on about 70% of occasions!

Chris

Nice images Neil. I was all set up for the Jupiter transition, and then a blanket of cloud appeared and wiped my southerly view. Ah well.

Chris

Greetings Claudio! I lived in Varese for 8 enjoyable years and developed my interest in astronomy there.

Chris

Worth looking at the Abingdon Astro Soc website - they (ie we) use a darkish site. The Ridgeway has some fairly dark spots as well.

Chris

Judging by what pupils look like when someone has taken certain drugs, maybe this can be induced with certain "substances", including legal ones such as caffeine and ethanol?

Chris

View with a 180 Mak. each is 2000/5000 frames. Part of a 50 minute sequence - cloud stopped play!

Io is visible (correct orientation) just above and the the right of the shadow as a lighter spot. Nothing like the result from a C14 of course........

Chris

Very nice! Good to see the C ring showing and Enke, with a reaalistic colour rendition overall.

Chris

In my 180 Mak, my 10mm Baader Ortho and a 9mm Circle T both perform very well indeed (to my non-expert eyes). While I like the FoV of the BSTs, (I have 8, 12 and 18mm) I do find the reflections I see of bright targets like Jupiter a bit distracting as they move across the field when you move your eye slightly. 

Chris

Very nice indeed......oh for 14"!

Chris

Brilliant detail! I imaged J at the same time with my 180 Mak. The difference in resolution is very obvious.

Chris

Some good potential detail there Trevor!

I struggle with an IR mono filter with my 180 Mak - I wonder if this is because although an IR filter reduces seeing issues, it of course reduces the resolution quite a bit (factor 1.5 roughly). This may be less of an issue with a larger aperture, but maybe is an issue with only 180mm. Views?

Chris

I've only ever seen the C ring twice with a large observatory cassegrain, but not with amateur scopes in recent years. Enke seems very difficult with my 180 Mak - I've had hints once or twice, when Saturn has been higher in the sky. It does show up in a stacked image though.

Chris

5 minutes ago, neil phillips said:

Yes Chris i dont doubt it. It will have a de smearing effect. The reason we bother to put something else in the imaging train. I am still finding my feet. You likely are more clued up on it than me. ADC newbie alert. Your thoughts on my question regarding null position correction Chris ? 

Not sure. With my set-up, I have the Barlow inside the nosepiece of the camera, which goes into the ADC which in turn goes into the flip mirror, which is in the back of the scope (1 1/4" adapter). With this, the levers are on the rhs. My usual setting is one 45 degrees up, one 45 degrees down. this removes the visual AD on Jupiter or Saturn when it is say 20 degrees up. If I move the levers to the central (zero) position, the AD is obvious, it disappears as I open the levers.

Re colour balance, I think Vlav's adjustment above is about right - what I see through the EP. many images have had the colour saturation wound up which looks pretty, but it's overdone in my very humble opinion. The original looks greenish on both my monitor and my phone.

Chris

1 minute ago, neil phillips said:

Still learning about the ADC Chris. But the better images did coincide with the ADC being used. did a ton of earlier shots without it for comparison. 

I've tried with and without with my Mak, and I see definite improvement even compared with rgb align in AS or Registax. Visually with an EP I would say I can see more detail in J's belts and certainly more ring detail with S. Improves the muddy appearance of S near the horizon too.

Chris

Good detail for 5" Neil. Ate you finding significant improvement with the ADC?

Chris

Nice images. I am afraid that poor weather may well wreck this year's Jupiter season!

Chris