WANTED - Altair Astro Starbase
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By AJ-DE
Hi All, I have a Star Adventurer but have had problems getting consistent results even when setup was as near to perfect as I can do, (this was focussed on due to this issue).
It took me a while to find out that when the eyepiece is is extended for focus it is very loose, so loose the graticule moves indipendantly of Polaris / background.
I have asked the supplier, "Astroshop.eu", to highlight the problem and ask for their feedback.
Question to Astroshop.eu:
I have had a constant issue with Polar Alignment. As I cannot use it so often, (visibility), it has taken me a while to identify the problem. When I adjust the polar scope focus the eyepiece is so loose that the graticule moves a lot laterally in all directions in the view. I can send a video but I think you can understand what I am saying.
Basically I must be getting something very wrong or there is an issue with the product. The thread is so loose it is entirely unstable.
Please advise what we can do about this.
Answer from Astroshop.eu:
1. "I'am sorry to say, but this is very normal and does not affect the function of the star adventurer".
2. "My collegue confirmed that this will not be a issue".
I have subsequently asked the guy to ask his colleague again, but some time has gone past and I have no further reply.
I think it is clear enough from the text and would really appreciate some experienced answer, any comments very welcome.
Additionally here are the videos I have sent to show them, (hand holding the phone so a bit shaky but issue can be seen. I'd really appreciate some help before I spend too much time again tring to get it to work, for reference the eyepiece wobble is around 3.5 graticule intervals, so not small. As it's full of grease it took me a long time to see how poor quality the Polarscope build quality is.
https://drive.google.com/file/d/1VC1p30t8n45oS6fkdxjkztrnoR1r7c6x/view?usp=sharing
https://drive.google.com/file/d/1mjBaecqTmIhXgJUC-dERRYBb-LaryLMN/view?usp=sharing
Thank you all, Andy
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By andyrawlins
Hi All
After much research, primarily on this site and The Binocular Sky, I got hold of the above binoculars. I spent ages writing a review specifically for this site of what I found, as a thanks for all the advice I had received. By the power of idiocy I then managed to post it on Cloudy Nights instead (I had both open in my browser). Too much Christmas port I guess
Anyway, too late to take it down as some have already replied and I guess I shouldn't post the same thing on two sites so here is a link to my review on completely the wrong site No offence at all to Cloudy Nights but I wrote it with the Stargazers Lounge audience in mind and it may make less sense on a US site.
Comparison of Pentax SP 50 WP 10x50 and Nikon Action EX 10x50 CF
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By Hena
Hello all,
I have come to you all with the "too much asked question".
I have been using the telescopes from local Astronomy group since few years, and now during these Corona times, it is harder. So now I have decided to invest some money on getting myself a scope, and would so sooooo would love your inputs. My main concerns are:
I may use it only once a month or so, I wanted something that I can handle (maybe >10kg).
I don't own a car, usually I use a bicycle with a carrier to get around the city.
(I had a look at the second-hand (5-7 yrs old) Skywatch MAK 127 Cassegrain that my friend was selling with its mount and accessories. I felt it was too massive for me. Especially if I am getting it to a park and setting it up alone).
I would like to have a look at celestial objects and also at deep space.
As far as I know for deep space, I would need a f5 or something with similar focal ratio, and for planetary object a higher focal length (f10 or more) is better.
I looked into MAK 90-1250, but felt like it might have very narrow FOV. So I am lost here.
My budget is small (I know that is the biggest problem). I can spare maybe 200€ to 250€. I know its not enough, so I am hoping to start with a decent one (not awesome) and then work my way up. I so need your advice on what might be good parameters to look for
- I was thinking Newtonian around f8 or so
- Since its my first scope, maybe get something small and something that I can get comfortable with and use with a bit of ease before getting expensive ones.
- Also definitely not a Dobsonian mount, I need something that I can set up on lawn or pavement.
https://www.bresser.de/en/Brand/Bresser/BRESSER-Venus-76-700-AZ-Reflector-telescope-with-Smartphone-Camera-Adapter.html
Is this a good one to start with? Look at planets and maybe some deep sky ones
https://www.astroshop.de/teleskope/celestron-teleskop-n-127-1000-starsense-explorer-lt-127-az/p,65881#tab_bar_1_select
I also has my eye on this, but I cant find much reviews Any other options are quite welcome.
I tried to setup and use the telescope in the picture, it was quite hard to do it alone and move it around.
Thanks a lot. Sorry for the saga...
Hena
1417b25b-42c8-4909-b731-25c88c7dce42.jfif
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By Zermelo
I saw a suggestion somewhere (possibly in SGL) to attach lights to your tripod legs (dark-adaption-friendly ones, of course). The idea being to avoid accidental collisions, especially at star parties or outreach events. We experience this quite regularly at home too, so I decided it was worth pursuing (and also, as users of go-to functionality, I’m getting tired of repeating alignment operations throughout the evening).
The very simple idea was a (removable) clip for each leg, each with an LED. I briefly considered a self-contained battery to power each, but decided that charging them was too much hassle (and I also doubted finding LEDs that would operate at such low voltage). Instead, they would be fed from the USB port on the power supply I previously rigged up. I thought the LEDs would be more noticeable if flashing, and found these.
My SkyWatcher 150i tripod has 1.25” upper legs and 1” lower. Since collisions are most likely with the lower legs, it was that diameter I worked with. I looked for plastic pipe clips of this size (the most common ones are 15mm and 22mm used for plumbing) and found these. They have a hole for a fixing screw that can be used to hold an LED, and they have a hinged collar for holding the tube, which preserves a gap that allows electrical connections to pass.
The screw hole in the clip was wide enough to admit the LED body but not the rim. To allow the LED to protrude from the clip I drilled out the holes a little wider, and about 2/3 of the distance through the clip. The LED could then be pushed through until the rim engaged, and the terminal leads were bent into a succession of right angles to guide them to the top of the clip. I found some twin speaker wire in my junk box, and soldered lengths to each LED’s terminals. The clips have a channel along the edge to allow them to be ganged together. I opened them out with a needle file so that the speaker wire was a tight fit when pressed in – this was for strain relief.
I covered over the soldered joints with some scrap plastic strip, screwed into the clip, and pushed some Araldite into the hole and around the exposed metal, to prevent shorting:
These LEDs seem to work on 5.1V without needing a series resistor, so I twisted the positive and negative ends of the three speaker cables to run directly in parallel. I cannibalised a USB cable for its male socket, and soldered it (with a bit of its flex) to the speaker wires. The USB wires were quite flimsy, so I reinforceded the joint by gluing, sliding over some bits of thin plastic tubing and wrapping with duct tape.
The clips are a very tight fit onto the tripod legs; with hindsight I’d try to find some slightly larger. I’d planned on adding and removing them as needed, but decided to leave them permanently attached:
Total cost: £8.39
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By endless-sky
I have already posted my first astrophotographic session report in the telescope review thread: Tecnosky 80/480 APO FPL53 Triplet OWL Series - Review. But since that is more of a general review/diary of my experience with the new telescope, I feel some of the issues I am having are being buried and they will probably get more visibility if I post them - in a more synthetic version - in a dedicated thread.
So, a few nights ago (October, the 5th) I took out my new telescope for its first light. All the photos have been taken with the 0.8x flattener/reducer and the Optolong L-Pro 2" filter attached to the reducer. The camera is an astromodified Nikon D5300. The only processing the following pictures have consists in this:
- AutomaticBackgroundExtractor
- ColorCalibration
- Stretch
Here we have a 90s shot of M31.
And here's a mosaic generated with the AberrationInspector script.
What I do like:
- tightest, smallest, roundest stars I have gotten since I started doing astrophotography at the end of January. Obviously comparing it to what I have been achieving with a kit 70-300mm zoom lens, these can't be anything else but better by orders of magnitude
What I don't like:
- star shape not consistent in all areas of the image
- residual chromatic aberration, especially on stars that are not round: there's clearly some red and blue edges visible
I didn't expect this from an apochromatic refractor, but maybe it's just because the stars are kinda "smeared", so not all light is focused at the same spot? I don't see this around the center of the image (or, at least, the problem is less pronounced). Maybe I have some tilting in my imaging train/sensor?
I have been doing some reasoning about it and it seems like a combination of tilting and/or backfocus spacing. According to the following image about backfocus spacing:
if the stars are elongated radially, the sensor is too close, if they are elongated tangentially, the sensor is too far. But to me it seems I have a little bit of both: in the top right corner, for example, the stars look radially elongated, in the bottom right, they look tangentially elongated. Top left they look tangentially elongated, bottom left also, but a little less. Seems like there has to be some tilting as well, otherwise they would all have a symmetric shape on all corners, correct?
How do I determine - is there even a way - if the issue is due to tilting only, backfocus only, or the combination of the two? Is there a sure proof way of checking for tilting? Like, rotating the camera and taking pictures with, say, the camera at 0°, 90°, 270° and 360°? If there's tilting, the pattern of the star shapes should follow the camera, correct?
I also tried splitting the channels in R, G, and B components, doing a star alignment of the blue and red channels with the green as a reference, and recombining the channels. The blue and red edges become a lot less evident, which is good, but obviously the star shapes remain the same.
In my Telescopius gallery you can also find two other images, Capella and Capella Mosaic showing pretty much the same issues.
Also, one issue with the guide camera: ZWO ASI 224MC. When attached to the guide scope (Artesky UltraGuide 60mm f/4), I can't seem to get a "sharp" focus, I even tried on the Moon, and the best I got was a soft lunar disc, with some major features visible, mainly by change of color/brightness (the maria, for example), but no details. The image still seemed blurred/bloated. Is it because of lack of IR blocking filter? I tried the same camera attached to the main refractor, with the L-Pro filter (which blocks UV and IR, as well) and I could focus perfectly. Do I need an IR block filter for guiding or even if the stars appear a little soft, the camera guides just fine?
Matteo
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