ONIKKINEN

Hello and welcome to SGL

There are many targets that can be enjoyed from light polluted or bright summer skies with your scope! Other than the Moon which is always nice there are the 3 bright planets out and about: Jupiter, Saturn and Mars although of these 3 Mars is very small at the moment and will become much better later on in the year, but Jupiter and Saturn are a treat for sure. Open clusters (of stars) can look spectacular even in a bright setting with your scope so its worth having a look at those. Double stars are also interesting to observe, although less of a "spectacle" so to speak but trying to split a particularly difficult pair of stars can be very rewarding even in bright conditions. If you are interested in finding things in the sky yourself i will recommend a book called: Turn left at Orion. That book has easy to understand pictures and instructions on how to find the most common objects in the night sky, and also has plenty of dark sky not required type of objects to see, highly recommended!

As for the astrophotography side of things i would advice to leave that for later. Its an unending rabbit hole of spending money and things to learn and best delved into once you get your "astro legs" going with observing first. But once you do star to get the itch for astrophotography, the T2i you have is a good camera to start with.

Remember to have fun with the scope, that is sometimes easy to forget when learning new stuff!

9 hours ago, pipnina said:

I gave the collimation a good re-do tonight as it was getting dark. I managed to pry the M48-M42 adapter from the CC (some of these threads get well and truly stuck!) so the 2-1.25 adapter that holds the laser would attach to the CC. It does make it a bit softer, but not a huge amount. I do think it made things a bit easier though so thanks!

As you can see I took a quick 5 second luminance image of a star-dense region and the FWHM measurements are MUCH better than before. But visually you can still see something isn't quite right when you look at the corners. Maybe I need to attempt barlow lasering to get it as bang on as possible?

Also I wish GSO made their mirror cell in the same way as skywatcher... My 130P-DS threadlocked studs into the mirror cell, then used thumbscrew nuts to pull the mirror or push it further away from the cell block, with three locking screws that drive into the cell. Never had any issues with this and it was SUPER easy and intuitive to make it work. This GSO one however seems like they put about 30 seconds of thought into it and went "good enough!". I have to both have enough tension on the locking screws to allow the adjustment screws to actually move the mirror, while also leaving it loose enough to move the adjustment screws without too much strain. It's just poor deisgn, and from an OTA that costs a lot more than the equivalently sized 200P-DS...

I think a focuser upgrade will be in my future too, I think it just makes sense to ensure it's all held properly since my kit is heavy and if it fits my corrector and collimator more snugly and consistently true as well, that can only make things easier. I found I had to double check my laser multiple passes over when rotating it 90, 180, 270 etc to check it was all in the right place... The focuser wasn't always keeping it quite the same way every time. When you changed your focuser, how easy was it and did you have to do any alignments with that, like shimming etc? Or do you just have to re-collimate?

Many thanks again!

That result looks great, i would be super happy with that collimation! That few % fwhm difference will not be noticeable in a final image.

I installed the Baader diamond steeltrack on my VX8 and had to drill 4 holes for it to fit. Also had to enlarge the drawtube hole on the OTA just a little bit to make sure it doesnt freeze on me. An afternoons work at best, not difficult to do at all.

It comes with a couple of shims in the box to make it sit flush on different sized tubes. It also has full adjustment in pitch and a little bit in yaw to do final adjustments on centering it on your tube. Bit pricey yes, but well worth the cost IMO, one of the better purchases i have made for sure.

3 hours ago, Ags said:

Nice! Sounds like an RFT that can "do planets". It should be a great "sweeper" if you can get it to some darker skies. Nice to hear it splits doubles well too.

Just wanted to add that the Long Perng comes in two flavors - one with regular glass + lanthanum, and one with FPL51 + lanthanum. I think you have first one?

I've read these are also excellent solar scopes in white light and Ha, as the lens in both flavors of the scope appears to be well figured.

Yes, indeed mine is the more affordable one of the 2: https://www.teleskop-express.de/shop/product_info.php/info/p11438_Long-Perng-90-mm-f-5-5-Doublet-ED-Rich-Field-Refractor-with-2--Crayford-Focuser.html

Quoted from the description:

Quote

The adjustable 2-element objective has a similar color correction as a normal Fraunhofer achromat with f/7, but offers a significantly higher speed. This corrector is achieved by the lanthanum-containing special glass.

No mention of any specific glass type like FPL51, but just that "lanthanum glass". If it did have an FPL-something lens in it it would be marketed for sure so safe to say it does not. But i am pleased to see that CA on this one i can live with for the most part, but will try filtering that out anyway to see if Jupiter gives a bit more that way.

Clouds cleared suddenly and i put my new grab and go kit to work. The frac and eyepieces is in a backpack and a Skywatcher AZ5 + steel tripod is somewhat easy to carry out in one hand. I dont really have a backyard in my apartment complex, but a short hop across a road to a (fully lit 24/7 🙄) parking lot frees up the horizon down to 10 degrees - so barely enough to see the Moon and Saturn sweeping across rooftops.

And Saturn was the true first look through the scope, i mean it would be rude to look at something else! Pentax XW10 and a 2.5x barlow in a TS- 1.25'' dielectric diagonal for a comfortable power of 125x. Saturn snaps into focus very easily even though its very low on the horizon. The view isn't super stable, but it is actually not even close to the worse views i have seen of Saturn so i am very pleased at this point, but to test how well the scope holds collimation with the heavy chunk of glass that is the XW10, i cruised around Saturn keeping it close to the edges of the FOV and seeing if the image degrades. I am pleased to report that it does not and its sharp across the field of view so doesn't seem like there is any sagging in the focuser. There was something to the side of Saturn blinking in and out of view once i got a comfortable position and looked for a while, maybe a few widths of saturns rings away and im not sure it could be anything other than Titan which is surprising with the bright night skies. No hint of Chromatic aberration for Saturn at this power!

Jupiter was next, still with the same setup of 2.5x barlow and XW10. Here, i do notice the chromatic aberration as a quite bright purple edge around all of Jupiter. It does bother me a bit since purple is a very unnatural colour to see for me (newtonians only before). I let the view seep into my eyeball for a while and kinda just got used to it in no time, but i can still see it and i am thinking for Jupiter i would be better off with some kind of purple fringe eliminating filter. I saw 2 rather obvious dark bands and a varying number of other lines across the disk. I see some kind of "mush" at the edge of one of the bands that keeps coming and going with the seeing (which was pretty good actually). Occasionally i see some spiraly-swirly structure in place of the mushy something. Surprised to see that a 90mm aperture scope can give pretty nice views of planets too! Almost forgot to write that i started observing Jupiter with 3 visible Galilean moons, but during observing a 4th one appeared from behind Jupiter! Actually checking now it was Europa and it was in front of Jupiter and not behind, but this i did not spot before it had crossed the disk.

Gave Mars a brief look but at 125x its a very small reddish not quite round disk. Cant really say more on this one, needs more power and a few months for Mars to come a bit closer.

Looked at the Moon for a very short while. Its basically licking the rooftops and the views were awful really. But here too there is the purple fringe. Bothers me less since the Moon is enormous and i dont feel like the view is bathing in the light, but if i can see it it probably means there is some contrast and sharpness loss so another target to test later if/when i get some kind of filter.

Just as a passing thought before heading back inside i pointed the scope towards the double double in Lyra and was welcomed with a very obvious split of both doubles. Quite pleased with the optics at the moment! Clouds are coming and going and most of the sky is covered in what looks like haze, so pack up the stuff and head home.

I did get the feeling that for Jupiter and perhaps the Moon i would be benefiting from some CA filtering.

And more power. Could definitely have used more power.

First light with a new scope, the Long Perng 90mm F/5.5 doublet:

What a beautiful scope! Must be a real planetary and lunar beast with that focal length.

Really had to scroll down to find out the specs, which are: 100mm FL and 24mm aperture. Id say it will be very underpowered for anything other than the handful of bright big objects out there. I cant help but feel it should be a bit bigger even if the price doubled.

The pictures shown in the site are from bortle 4, which is much, much better than the average sky condition for most so those examples are more of an upper limit than your average consumers shot.

Its not looking great IMO, but i dont think the target audience is the amateur astronomer but instead the tech enthusiast social media person or something like that.

Hello and welcome to SGL,

Amazon and other non-astronomy related storefronts should be avoided at all costs for astronomy purhcases. Especially so if the scope in question is a generic noname brand like the refractor you linked. Celestron is a well known and liked brand, but this particular model, the powerseeker 127, is and im going to be honest: Perhaps the worst telescope for the money in the world. The mount is flimsy and very frustrating to use, the views will shake and wobble for several seconds after touching anything in the scope. The telescope itself will not give sharp views in the center of the field of view and it only gets worse towards the edges (much worse). Both of these scopes are i would imagine so bad that there is a good chance you give up and throw them off a cliff and never look back.

To name a few stores closer to you:

https://optcorp.com/

https://www.highpointscientific.com/

There are many others (dont know that many stores on that side of the atlantic).

This one ships from the UK, but the prices are pretty good:

https://www.firstlightoptics.com/

If you have a specific upper limit in your budget we could advice better on which way to go. But still want to say again, that neither of the scopes you linked will give you your moneys worth! (there are scopes around that pricerange that would though).

And as a bonus, a review of the powerseeker 127 from Ed Ting:

Remember a few years ago Betelgeuse was dimming significantly? But now it seems to be up and running again. It could be perceived as less red if it dims significantly, at least i think that is the case when looking at Mars in opposition or when further away. I think that dimming event a few years back was due to some ejecta from the star forming a sort of dimming cloud around the star or something like that.

2000 years is also not that short for a massive star like betelgeuse and that could be enough time for a change in temperature along its natural stellar evolution path. 2000 years is also long enough to make it rather difficult to check the sources 😆, so could be or could not be right.

New scope finally arrived. Also, the heatwave ended which i am happy about but the clouds that came with that i am not 👎.

Long Perng 90ED F5.5

First impressions, above all, its much bigger in person than i expected (dont know why i am surprised) but the Skywatcher AZ5 + steel tripod feels like a pretty good match to this thing and it still fits in a backpack along with some eyepieces and other kit that i want to have with me so all good and fits the purpose i had in mind. Overall feels nicely built with all metal parts, pretty good feeling 2 inch crayford with a reducer knob, rotateable focuser to cover the fact that it did not come with rings and the sturdy padded case which is a nice bonus.

Feels nice for "only" 500€, but i suspect the price is due to low spec glass in the ED element, but that i will find out once the clouds clear and darken.

4 minutes ago, Franklin said:

Make sure it has the ND3 fitted internally. It's possible to buy the Lunt without it and if you weren't aware you could damage your eyes. I bought my 1.25" Lunt wedge from TS and it had no ND3 fitted (thought it was cheap). I fitted a Baader ND3 into the base myself and it all works fine with and without the SC filter. Polarising and Longpass 495 all work well and the Wratten #56 & #58.

There is some kind of filter between the prism itself and the eyepiece holder, i assume this is the ND3 filter?

I can sort of see something through either the prism or the filter, but with both its very dark and only a peep of my 1200 lumen headlamp gets through.

8 minutes ago, johnfosteruk said:

Here's a lot more detail on the NIRCam filters:

https://jwst-docs.stsci.edu/jwst-near-infrared-camera/nircam-instrumentation/nircam-filters

 

Thanks, nice and easy to understand graph in there:

8 minutes ago, Ouroboros said:

Sorry if this has already been covered here but is there an explanation somewhere of what the different colours represent in the JSWT colour pallete/s? 

Itching to know this myself too. There is bound to be some technical explanation sooner rather than later.

Looks like JWST is a rather fast instrument so there will be an enormous pile of data left for decades after the mission ends. Who knows what will be discovered?

What a time to be alive!

6 minutes ago, Sunshine said:

It's the difference between my 4'" refractor and a 16" dob.

Well all right then. Looks like ill need a 16'' dob then 🤣

If i had to guess they have somehow blueshifted the spectrum to be more like one would expect from a real colour image. The reddest spots would be the furthest Infrared targets in that case.

Would love to hear a technical explanation for the chosen palette.

6 minutes ago, Laurieast said:

HST Same target. 

 

Oh wow, the difference is really stunning.

3 minutes ago, gilesco said:

Yes, on screen it looks under- well , not overwhelming, but take the full thing and look a bit deeper, you start to realise that there is real depth to the image.

They did a really poor job of showcasing this.

I agree, the stream was anemic!

Quote from the article: https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet

Quote

This deep field, taken by Webb’s Near-Infrared Camera (NIRCam), is a composite made from images at different wavelengths, totaling 12.5 hours – achieving depths at infrared wavelengths beyond the Hubble Space Telescope’s deepest fields, which took weeks.

Only 12.5 hours? Imagine a week long integration...

Here is the full thing:

Unbelievable!

Gravitational lensing for sure with those warped lines around the center. Real-ish looking colour palette, really like that!

Lenscap was on all this time and just now found out?

Someone is quickly taking an image of the orion nebula with their 80ED in an effort to fool the masses.

I dont trust bahtinov masks, even for DSO imaging. My star sizes decreased noticeably after switching to statistics (HFR) and visual based focusing. I think just visually looking at a dim star is better than a bahtinov mask for focus! But some folks like them, so user error and differences in the masks could play a part too.

I am no planetary imaging veteran and only dipped my toes a couple of times to attempting Jupiter imaging with a DSLR (in raw video mode). Focusing was a real pain in the backside with having to look at the small screen on my 550D, but i found that visually focusing on the Galilean moons and a shadow transit of Ganymede was what were the easiest. The shadow of Ganymede disappeared if out of focus slightly and appeared as a sharp and quite obvious dark disk on Jupiter when in good focus.

Not sure i have ever been more excited about astronomy news, just show the image damn it!

14 minutes ago, pipnina said:

Hmm, thinking about my setup when taking that image... I just put my telescope back to the position it was in.

It does seem like the weight of the camera/filter wheel/coma corrector would have been weighing roughly on the lower left part of the camera, but not quite the 45 degrees this image analysis would suggest.

I also took images last night of the bubble nebula, although those weren't focus tests and as such have much longer exposures, so I don't know if they'll be as easy to analyse accurately...

By eye, matters in this image don't seem as bad, but the objects are on opposite sides of the meridian, so one has the center of gravity of the camera pulling one way, and the other has it pulling in roughly the opposite direction in theory? What do you think?

NGC_7635_Light_002.fits 49.49 MB · 0 downloads

 

Edit: Alacant has stressed the importance of robust support, and no doubt at some point I will move things to a losmandy bar and puck, but the vixen style supplied with the scope is already rather long (skywatcher supplies 30cm I think, this one is much longer) and flipping the telescope from one side of the meridian to the other hasn't produced a shift in collimation on the laser since I followed one of Alacant's pieces of advice and removed the primary mirror clips and replaced them with neutral silicone sealant. So I am not sure tube flex can be blamed.

This one looks much better. I think this one had much better seeing also since your starsizes are much better compared to the focus test, but collimation looks better too for some reason. Top right corner appears to be the best according to Siril (pictured) and ASTAP image inspectors.

Star shapes are still a bit weird but that could also be in part due to guiding or something other than collimation (still guessing its mechanical, focuser most likely). But, i would say judging from the image that its still a bit out of collimation for some reason. But also i will admit that i would accept that as starsizes are pretty decent here and if binned x2 it would be hard to find something to complain about. Not sure how to proceed if i were you, but since your tube and mirror cell are good it leaves the sensor itself being tilted, focuser being unreliable or the mirror collimation itself as the causes. Or the collimation method you use is still somehow not quite ideal. Try the laser-through-CC method and see if something changes?