johnturley

You've captured Solis Lacus very nicely, clouded out for over a week here.

John 

14 minutes ago, gilesco said:

 

Dud telescopes go back to the distributor, the good ones get shipped to FLO.

From what I gather, there are very few (if any) dud Esprits, occasionally one requires the collimation to be tweeked.

John 

15 minutes ago, Victor Boesen said:

I would love to get a diagonal which I know I can rely on for some time. This was also the reason why I, as my first eyepieces, purchased and stuck to the Explorer scientific 82 degree series. As with many other decisions in this hobby, I feel like there are so many choices, many quite similar, and I just need to settle on one at some point

EDIT: The 2" BBHS diagonal does look very good though, and I really like the customizability and quality of it!

The Badder 2" mirror diagonals employ  larger mirrors (46 - 47 mm clear aperture) than most other makes, which could be of advantage with some longer focal length eyepieces with large field stops, also if used for imaging with a full frame sensor. I also like the click-lock mechanism of these diagonals.

I have both the dielectric (currently fitted to my 9.25 in CPC) and BBHS (fitted to my Esprit 150) versions, I've not really compared the performance of them (must do so some time), but the coating does appear brighter on the BBHS version., although nearly twice the price.

John 

43 minutes ago, Victor Boesen said:

The Takahashi diagonal is great for my small Evostar since it has such a short optical path, although I'm using quite a long 2"-1.25" adapter. I will try the shorter adapter supplied with my new scope and check how much inwards travel distance I have left. I'd love if the *future* 2" diagonal I end up getting will work in both scopes, but if one scope needs a longer light path and the other a short light path, this might be difficult From a little reading it seems that mirrors and dielectrics have a longer optical path than prisms. I will do some rough measuring in both my scopes to make sure it'll fit both

With a 2 in mirror (longer optical path) diagonal your eyepieces will focus further in, I have both the Baader 2in Dielectric, and BBHS Click Lock mirror diagonals, which have an optical path of 112 mm. The Baader 2in and T2 prism diagonals have stated optical paths of 100 mm and just 38.5 mm respectively, and will focus further out.

John 

On 08/10/2020 at 18:47, Victor Boesen said:

Thanks! I know I have to wait out the obligatory bad weather unfortunately The 24mm eyepiece is an Explorer Scientific 2" 82 degree eyepiece. I find it difficult to see if I need more inwards travel distance or outwards actually. Perhaps I'll try again tomorrow. What I do know for sure though is that it doesn't reach focus;)

I think that you will find that the ES 24mm 82 degree eyepiece will focus about 10 mm further out than your 1.25 in ES eyepieces, if they focus at a point near to the end of travel on your focusing mount you may need a short extension tube.

John 

11 hours ago, geoflewis said:

Thanks John, yes it's definitely shrinking, but also it's not at the pole, but rotating around it, so maybe was slightly out of view during this session.

Yes, I think for this reason it appears smallest around CM longitude 180, and largest around CM longitude 0. 

Truly amazing image, looks like the south polar cap is going to disappear completely within the next few weeks.

John 

2 hours ago, M40 said:

Oh if only I knew how to stack them :D, nope I quite simply bolted the DSLR camera body to the hyperion zoom and took individual pictures. I have a lot to learn about the telescope and even more to learn about the camera🤣. My son told me I need to change the shutter speed........ Apparently he is going to teach me some camera basics, lets hope some of it sticks 😎 The camera settings were 1/100 F00 iso6400. That should give you a clue as to how much I know about camera settings 

All the more remarkable for a single shot image taken with a DSLR, I don't know whether you can take movies with your DSLR, I process movies taken with my Canon 6D with Registax and Lightroom, but the problem I gather with the 6D is that the sensor is too large for planetary images, and that I need to use eyepiece projection with a 9.7mm (or shorter focal length) Plossl eyepiece to give a reasonable sized image scale. 

John 

Great image very similar to what I saw visually last night, note that the South Polar cap is looking really tiny, would not be surprised if it disappears completely as it appeared to do in 2005.

John 

14 minutes ago, Fozzie said:

i wonder if it was Nu Piscium.. (V)

 

 

There was a moderately bright star in the same high power field of view of Mars last night, however I knew that it was too bright, and too far away from Mars to be one of the satellites, looking at Skymap Pro, most likely to have been TYC-135-20-1 Mag 8.93

John 

49 minutes ago, Fozzie said:

Did any body pick out any Martian moons last night..  I had a tiny spot of light to the north of the planet (below), wondered what that would have been..?  (South was at 12ocklock and syrtis major at 9, the way i was viewing)

No sign of them visually even through my 14in, I assume that I would have to overexpose Mars to show the faint satellites on an image. 

John 

16 hours ago, Pixies said:

Hi John,

Do you think the south polar cap is getting smaller? I'm under the impression that it is.

I would not be surprised at all it it disappears completely, at least in amateur instruments, like it did in 2005. There are a number of reports indicating that it now shrinks more than it used to, suggesting that Mars as well as the earth may be experiencing global warming. I looked at Mars last night and to me the SPC was tiny, smaller than it appeared in late September 1973 (slightly later in the Martian summer) when I made some drawings, shortly before the onset of the global dust storm of that year.

Viewing conditions were quite good again last night (after having been very poor on 25-26 September), and I was able to use up to 250x on both my 14in and Esprit 150, which showed  similar levels of detail. I find that particularly with Esprit 150, the image gets quite dim at over 300x, so it surprises me when some claim to have successfully used 400x or even 500x with 100 mm scopes, to my eyes at least the resultant image would be very dim. 

I attach my best image from last night taken through my 14in Newtonian (possibly a bit over processed), which shows Syrtis Major, Hellas, Aeria and Sinus Sabaeus quite clearly. I also attach an image taken just 13 days earlier on 15.09.20, and I think you can notice a significant shrinkage of the SPC  between the images.  Both images were taken using eyepiece projection with a 9.7 mm Plossl, and processed in PIPP, Registax and Lightroom

John 

1 hour ago, johninderby said:

The Bresser with the Hexafoc focuser is different to the SW as they use extension tubes to allow a much greater range of in and out focus for visual and camera use.

The extension tubes are also required due to the very limited amount of travel on the Hexafoc focuser, only 45 mm. 

John 

I raised this issue back in 2005, the circumstances of the 2005 November 7 opposition of Mars were similar those of  the 1973 October 25 opposition, however whereas in 1973 the south polar cap was clearly visible, I couldn't make it out at all in 2005. Originally I put this down to poor viewing conditions from my location in 2005, but I subsequently saw a Hubble Space Telescope image showing the SPC to be so small, that it would have been hardly visible through many amateur astronomers telescopes. 

At the time the Russian Astronomer, Habibullo Abdussamatov, head of the Pulkova Astronomical Obseravtory in St Petersburg cited this as evidence that the current global warming is being caused by changes in the sun. Mainstream scientific opinion however put this down to variations in the isolation of the planet  arising from albedo changes (not sure exactly what this means), rather than increases in solar radiation. I understand that BAA records of observations of Mars go back to the early 20th Century, so it would be interesting to look at records over the past 100 years. 

You refer to global warming deniers, I don't think any scientific opinion disputes that the climate is getting warmer, and man made CO2 emissions will have some impact, the main question is what is the primary cause. I used to be a bit of a sceptic regarding man made CO2 emissions being the primary cause, but in recent years have been coming round more to the opinion that this is the case.

John 

Had my best night of the apparition last night, observing Mars from around 23.00 until 02.00, initially viewing conditions were not very good, as had also been the case when I briefly observed Jupiter and Saturn between 20.30 and 21.00. However conditions steadily improved as Mars gained altitude, and I experienced a brief spell of steady viewing at around 01.30, which unfortunately did not last long as conditions had deteriorated at 02.00 when I packed up for the night. This deterioration in conditions interesting coincided with the sky becoming clearer and less hazy, and a slight breeze springing up.

Originally I had my ZWO ADC coupled with a Neodymium filter rigged up on my 14in Newtonian, and a filter wheel containing both a Neodymium and Contrast Booster Filter rigged up on my Esprit 150. For most of the evening the Esprit was giving the sharper view, but at around 01.30 I removed the ADC from my 14in, and to my surprise got the clearest sharpest view of Mars I have had so far this apparition, using a 7m Nagler T6 eyepiece which gives 250x, and for the first time more detail was visible than through the Esprit. The South Polar Cap, Sinus Sabaeus, Sinus Meridiani, Mare Erythraeum, and Niliacus Lacus were all clearly visible.

It therefore appears that although the ZWO ADC can improve the view when objects are low down and suffering from atmospheric dispersion, however when this is not the case, it appears that it can actually degrade the image to a certain extent, which owners of the expensive Gutekunst ADC’s have suggested. I have no intention of spending £ 3.5k on a Gutekunst ADC, but may consider if I read positive feedback a Pierre Astro one at around £400.

 I also took the opportunity to compare the Baader Neodymium, and Contrast Booster filters with no filter. Both filters gave a slight, but not dramatic increase to the contrast to the dark areas on Mars, and I couldn’t really decide which gave the more gain, but as mentioned in another post, I don’t particularly like the yellow cast that the Contrast Booster gives.

I attach an image processed from a video taken with my Canon 6D digital SLR using eyepiece projection at around 00.40, which was before the brief spell of steady seeing, and has not come out as well as I would like, and shows much less detail than what was observed visually. I am aware that I would get much better results with a dedicated Planetary Camera.  I tried using the 1280 x 720 setting which gives 50 FPS rather than the full HD 1920 x 1080 setting which gives 25 FPS, but this appears not to have been a success.

19 minutes ago, markse68 said:

but less contrast? I’ve got a “mars type b” filter which makes the planet really red- it does increase the contrast of dark features but dims the image a lot and the redness is pretty intense!  I’m only really thinking mars here as the giants show plenty of detail on a good night

In my opinion (I own both) I wouldn't say that the Contrast Booster Filter gives any noticeable increase in contrast over the Neodymium, and I don't like the view through a deep red filter either. A light yellow or orange filter does enhance the dark features slightly, without making the overall view look totally unnatural, its all very much a personal opinion though, and some observers prefer no filter. I think the larger the aperture, the more advantage you get from using a filter, and that there is little gain with small apertures (100mm or less). 

John 

I don't like the yellow cast the Contrast Booster imparts on planets, and much prefer the Neodymium filter which gives planets a much more neutral looking appearance,

John 

Thanks Alan

I've had a quick look at Magic Lantern, but it does appear a bit overcomplicated for me, however I'll look at in again in more detail later, not sure whether it will help with my planetary imaging, also don't whether the Raw images will work with PIPP and Registax. 

John 

28 minutes ago, Davey-T said:

The 6D has two different compression options available one called ALL which compresses one frame at a time and one that compresses multiple frames at once, it lists 640X480 as a video option but the ALL compression doesn't work at this resolution, whether it's one to one crop mode isn't clear from the specs.

Dave

I've had a look at my camera and manual, you can do both the 'ALL' and 'IBP' settings  at 1920 x 1080 (full HD), 1280 x 720 (HD) settings, but just IBP at 640 x 480 (SD), which would be best.

The 1280 x 720 setting also gives you 50 rather than 25 frames per second, will this be better, just 25 or 24 (in the case of 1920 x 1080)  and 25 for 640 x 480.

I originally assumed that 1920 x 1080 would be best, my camera is currently set to the default of 1920 x 1080 IBP.

John 

3 minutes ago, Tommohawk said:

I just thought I'd post my best effort with my Canon 550D DSLR to show what can be achieved - IF you can use uncompressed video. This was done with a Skywatcher 200PD, so a budget scope, with a 5x powermate, 550D using video crop mode It's clearly not to the same standard as a dedicated planetary camera but it's fair I would say.

I looked at Magic Lantern software -  which apparently can be downloaded to your camera (I've never tried this) - but I dont this it will help. It appears that the 6D just wont do uncompressed or RAW movies at all - unless someone knows better?

Superb shot, like you say I don't think that there is a method of doing uncompressed videos with my Canon 6D, unless there is a 6D expert who can tell me otherwise, and show me how to do it. 

John 

I think that I'm inclined to concentrate on getting the best out of my existing system at least for now, I'm just put of by the problems associated with a trailing USB cable in my observatory shed in the dark, rather than the cost of a new planetary camera and laptop. Its a pity that, at least as far as I am aware, no wireless planetary cameras available at present, maybe these will come in time. 

John

39 minutes ago, Tommohawk said:

In your image editor there should be a way to crop the image. You mentioned Lightroom - see this help page

I agree.... a powermate, whilst excellent, isn't your priority. You need to sort your image capture first - find a way of doing uncompressed video, stack multiple stills, or bite the bullet and go for a planetary camera.

Thanks for the info, I've had another look in Lightroom and had some success with the crop function (see attached image), it wasn't obvious, and this is the main thing I been trying to find out how to do - Many thanks!. With the amount of detail I have captured on Mars, I don't think it would look better if zoomed in any further. 

I don't think that there is a method of doing uncompressed videos with my Canon 6D, unless there is a 6D expert who can tell me otherwise, and stacking multiple stills would be too fiddly and time consuming for me, and wouldn't alter the image size anyway. 

5 minutes ago, Nik271 said:

There is also a method for producing a higher resolution images from many lower resolution ones called 'drizzling' This is done when you can take multiple images which are lower resolution than you telescope can provide and then use software to get a higher resolution image by exploiting small variations of the image data. It was pioneered for Hubble since its cameras are of lower resolution than the optics can deliver. I don't know much about this but there should be people on this forum who know how to use it.

Thanks for the info.

There is drizzle function in Registax, which enables you to enlarge the image, however when I tried this the results were awful.

John 

5 minutes ago, Nik271 said:

 

                                          

 

For comparison I then rescaled your image as if was taken at the full resolution: 3600x5400 and again cropped at 448x448:

 

So if you can image at your full resolution you will certainly get larger planetary images (in terms of pixel size) and there is no need to go all the way to F57, something like F15-F20 will do. Most of the spectacular images that people post are with telescopes like a  14inch SCT at F20. A well-collimated 14 inch Newtonian working at F20 should produce very similar images. 

Nikolay

 

Nikolay

How do you crop to enlarge the image, I've asked this question several times before, but so far nobody has been able to provide an answer, and I was coming to the conclusion that it was not possible. 

To be honest I'm not convinced that using a Barlow would give better results than eyepiece projection, which is one reason why I'm a bit reluctant to spend £300+ on a 4x Powermate. 

John 

John 

51 minutes ago, Nik271 said:

 

 

These are massive focal ratios indeed, the images must be dim and hard to focus. Fundamentally eyepiece projection is no different from prime focus with a barlow, both serve to increase the size of the image on the sensor. The reason your images are too small is the change of resolution when recording video: from 20Mp sensor for photos to fullHD video which is a sad 2Mp. That's 10 fold loss of resolution so the image covers 10 times fewer pixels and is about 3 times smaller by diameter than what it could be.

 

Nikolay

 

Hi Nikolay

The image size is exactly the same regardless of whether I do a HD video, or take a single shot photo as with my images of Venus and Mercury.

The 'Live View' image is actually reasonably bright in the case of Venus, Jupiter, and Mars, but dim in the case of Saturn and Mercury, making focusing difficult.  In addition when I tried to take a video of Saturn, the MVI image appeared to be too dim for Registax to be able to find Align Points., and enhance the image.

John