PlanetGazer

Thanks for sharing! Just found other courses that are astronomy related, if anyone is interested.

10 hours ago, Ricochet said:

Adjust the secondary to get the doughnut under the crosshairs. Once this is done adjust the primary to put the centre spot in the middle of the doughnut.

My next mission before the end of the week, Thanks!

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I've just seen you list your location as Arabia. Given this, planet altitude will be less of an issue but I believe that cooling will be more of an issue. A telescope with a larger, thicker mirror takes longer to cool and your location may be prone to such rapid temperature drop that the mirror can never catch up. I would be inclined to fit a fan behind the primary to help speed up cooling. You should experiment to determine whether you get better performance with the fan still running or turned off once observing, but having it running while the mirror is out to cool should help. Having the telescope outside in the shade for as long as possible before an observing session will also help as you have found.

Indeed, the ecliptic plane is well positioned most seasons, in my location. I took a group of people, not interested in astronomy, and they were impressed with the views of Jupiter and Saturn (SW 130), now they'll bring their kids to observe!

As for the temperature difference, I was thinking of getting a fan for the 10 inch, but then I thought it's the temperature difference between (and correct me if I'm wrong) the mirror and the the surrounding air that cause the tube currents. The scope is stored in a cool and dry room (my office), and just before packing the mirror should be very cool, and AC is on in the car until reaching the observing site. Then I'll have to wait for aperture to reach equilibrium with the surrounding warmer temperature. It's the opposite over here, outside temperature is higher than home temperature.

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It is related to the aperture of the telescope. A 250p is almost 2X the diameter of a 130p so the tube of air you observe through is almost 4x as large. You need this larger area of air to be stable in order to not see turbulence. The 250p also has a resolution almost twice that of the 130p so you can also see turbulence that is half the size of the turbulence that the 130p can see. 

It makes logical sense, thanks for the help!

1 hour ago, Neiman said:

 - so that’s photography AND Astronomy that to have to learn, 

 

If that's the case, then waiting to learn one of them first could be a better option. For both the budget and your patience

Good question, can't wait to hear the replies.

I've read that there are special DSLR made for astrophotography named D610 Nikon . Not sure about it though, and it's pretty expensive.

On 22/08/2019 at 22:15, Alien 13 said:

I used to clean my old Charles Frank mirror once a month for years and never had a problem with any damage so not sure why people are so afraid of doing so....

Alan

Turn Left at Orion is a famous book, and in it, the writer instructs not to clean the mirror at all

As mentioned in previous posts, you are looking for freedom find feature in a GoTo telescope. I have a 10 inch Dob GoTo, and it has the freedom find, you can manually move it and still it would track and slew to objects.

This page explains the freedom find feature:

http://skywatcheraustralia.com.au/knowledge-base/

Note that GoTo alignment is not straightforward and will require some time for reading the manuals to understand how to align it and make it work.

Do you find any problems when carrying the 130ps? 2 flight of stairs, at least, is always necessary.

8 hours ago, MarsG76 said:

Still looks slightly off... the Cheshire reflection needs to be in the middle too.

 

I'm guessing the secondary needs to be adjusted?

On 24/08/2019 at 16:25, Ricochet said:

It is quite difficult to take a photo through a Cheshire but everything except for the shadow of the secondary should be centred under the crosshairs. In your photos it appears that this is not the case. You also don't have the focuser and/or Cheshire far enough out to see if the secondary mirror is centred under the focuser. However, none of this will prevent you from focusing the telescope. Focusing is simply a matter of having the eyepiece the correct distance out from the telescope. With respect to the planets, the low altitude will mean the atmosphere will often defocus the image, especially if you are observing over houses etc. I suggest you try focusing a high star. If you can focus the star then you have the correct adapters and extensions in your focuser and will also be able to focus the planets if the atmosphere allows. If you can focus a star but not a planet then consider more carefully what you are observing over and if changing the positioning of your telescope or the time that you observe will give you more favourable conditions. 

Yeah I wasn't satisfied with the photos uploaded as well, the doughnut wasn't as clear as I wanted it to be. I knew the cross-hairs did not coincide, but I was focused to get the hole centered in the doughnut. Do I have to keep adjusting the primary for the cross-hairs to align? or do I need to adjust the secondary. I will post another picture with the focuser extended.

I had a problem before when trying to focus with my 250p, planets were high, I tried using my old SW 130 f/6.9 and the planets looked crisp clear, could have been the collimation or mirror temperature. I was also worried it could be something wrong with the optics. But tonight, I managed to get acceptable views of Jupiter and Saturn, I left the scope outside for an hour to avoid temperature difference, and with today's collimation, it may not be perfect, but it was a noticeable improvement from what it was before, (could have collimated it before with tubes not fully extended). Though I'm eager to perfect the collimation.

I have done the star test on AlTair, and it seemed ok to me.

Another question comes to mind, is atmospheric turbulence more noticeable in low focal ratio scopes? or is it related of how well collimated the scope is? As I noticed that my slower scope show better views of Jupiter when low in the sky, than my fast scope (250p).

edit: Typo

Good Afternoon

I have been trying to get my SW 250P (f/4.7) to the best possible collimation as I couldn't manage to focus on any of the planets so far. I just collimated the scope to ready it up for tonight's session. Your feedback is much appreciated!

Welcome FileraBe 

I'm sure there are great non light-polluted sites in Switzerland.

Enjoy the Sky

I have been fiddling with both on android, and I'm leaning more towards SkySafari now. On it, you can set the limits of brightness magnitude for stars and DSOs which will reduce the congestion on the map, more functionality and options. But still, I prefer the general look and navigation of Stellarium. Tempted to have both 🥴

Why not use something like this battery and the adapter in the second link? which I assume have more capacity

https://www.amazon.co.uk/Sealed-Lead-Acid-Rechargeable-Battery/dp/B002S4T0F2/ref=sr_1_3?keywords=Lead+Acid+Battery&qid=1566424113&s=gateway&sr=8-3

https://www.amazon.co.uk/Battery-Cigarette-Lighter-overload-protection/dp/B01CDUU536/ref=sr_1_3?keywords=battery+to+car+adapter&qid=1566424150&s=gateway&sr=8-3

I use a similar battery with a different brand (cheaper locally), and no problems so far. Though it's for the best if you wait for more comments on this, as I'm only a beginner.

On 20/08/2019 at 19:07, John said:

Are you going to use a coma corrector in an F/6.3 dob ?. I don't find that I need one with my F/5.3.

At which focal ratio do you usually start needing a coma corrector?

Sorry for going off topic😅

So I'm referring to the main astro-softwares that you use during your sessions on your phone or tablet, and found that most of people use mainly those two softwares on their phones. Laptop versions of the software are different products and are not the focus of this topic.

So which do you use and why?

My experience:

I personally have Stellarium plus, and the free version of SkySafarai, so I have an understanding of how the user-interface of both works, I have been researching the extra features in the SkySafari Pro, and have figured the following so far (please correct me if I'm wrong):

* I'm aware that both let you control your GoTo telescopes

* I personally find current version of Stellarium to be more user friendly and easier to navigate the sky manually , could be the configured settings though

* SkySafari has more options to the search bar, e.g. "Tonight's Best" based on your location, also a menu of Messier catalog with a highlight of those currently visible at your time and location, others like best deep sky objects

* SkySafari has this wonderful feature of creating an observing list, very helpful to plan your session and share and download with/from others

* Stellarium Plus has a database of around 1.69 billion stars,while SkySafari 6 Pro has around 100 milion starts (don't think it's important as most of them aren't visible in amateur telescopes, I think I read somewhere that only 25 million stars are possible to observe with our telescopes, up to 15th mag, wonder if any of you have tried to push this limit)

10 hours ago, lenscap said:

Hi PlanetGazer,

You can import observing lists into the free version of Skysafari.

If you import it from the online repository within Skysafari using: Observing/ObservingLists/Import from Online Repository it should just work.

If importing to your PC or phone from elsewhere, make sure the list has a ".skylist" extension and place it in-

<top level of SD card>/SkySafari/Observing Lists/     or, if using internal storage,    Internal storage/Skysafari/Observing Lists/

This is for Android, iOS will differ.

The Skysafari manual is here;      https://skysafariastronomy.com/support/manual/manual.shtml

Good luck.

Hello Lenscap

Thanks for the reply, I just double checked the free version. There is no observing section.

I checked on the pro and the plus version on some videos , and it seems to have an observing section. So I guess that answers my question.

Regards

Great work! can't wait to see the final piece!

So I just downloaded a couple of observing lists one of them is the light polluted skies list, it opens on the Notepad++ just fine (on my laptop), I tried to open it up with Stellaruim on PC but I guess it's not compatible, however I heard you can use them on SkySafari App on your phone, which will be convenient if I link up the software with the GoTo I have,

I have Stellarium + and Free SkySafari on my phone, both won't recognise the list, do I have to purchase the SkySafari 6 Plus or the SkySafari 6 Pro to access it?

P.S i wonder if there is a dedicated observing list for very dark skies, that would be great for my next camping trip!

Thanks all for the information! Much appreciated

This videos helped me the most when I learned my way around EQ mounts, hope this helps

On 09/08/2019 at 15:40, Louis D said:

If you have a 2" focuser, I'd look into getting a 30mm or so wide field eyepiece like the ES-82 or APM UFF.  I enjoy scanning wide field views of rich star fields as much as observing individual targets.

May I ask what difference does it make having a 2" focuser compared to the normal 1.25" focuser ?

Don't you think a 12 inch non-GoTo is not the perfect starter scope? sorry I don't want to put you off or sound negative, but I think it's better if you check this exact scope at a store or better the the local club/community before buying. This is a truss scope, which I assume you have to assemble and de-assemble it every time you move + not the most convenient portable scope for a beginner.

12 hours ago, Wavseeker said:

Well I went to a stargazing club today and I am quite puzzled again. A Schmidt cassegrain is suddenly interesting again since its very portable and I can do astrophotography with it. And I found a celestron 8SE on sale at optcorp. Anyone here has some experience with them? 

 

Hahaha, I'm amazed how the evolution of your dilemmas matches mine , I was just looking at Cassegrains an hour ago

4 hours ago, Demonperformer said:

I think you will enjoys the views you get with it.

There are no doubt people who will advise you to stock up with extra eyepieces (and other things), but I would advise patience. One of the greatest skills you can develop is to learn to "see" rather than just "look at". This takes time and patience. The longer you observe an object at the eyepiece, the more you will see. Start with the EPs provided and upgrade when you know why you are doing it. What do you expect your new purchase to achieve that your current gear doesn't? If you don't have an answer to that question, you can find yourself spending a lot of money to very little advantage (I speak as one who did exactly that!).

The only other thing you really need are clear skies (yeah, like that's going to happen!) and a dark site from which to observe. One thing you might find useful, however, is a planisphere. Some (including me) find this easier than a standard star atlas. Dial in the date and time, hold it over your head oriented to the north, and it matches the sky perfectly.

You are in for some fun nights with that scope ... enjoy!

Very good advice! Couldn't agree more!

After reading your latest comments, I can assume you are facing 2 dilemmas:

1. is 10 inch v 8 Inch,

2. having a classical, push to , push to + or a GoTo.

I just faced it a week ago and I took my decision. it will come down to the following:

For choosing between 8 inch v 10, it'll come down to portability and your ability to carry the 10 inch easily or sticking to the easier 8 inch , the best telescope is the one you most use. As for the technical difference in terms of light gathering, theoretically the 10 inch collects 56% more, yet a lot of members report that the difference is noticeable only for deep sky and faint objects. Not to mention that the 10 inch is a fast focal ratio (F4.7) so will require better eyepieces (EP), while the 8 inch (F6) is more forgiving on EPs, though some members mentioned that you can always mask the 10 inch down. Also collimation is more required in the 10 inch.

As for the guiding systems, it's purely personal, if you think you will enjoy learning your way around the sky with maps, you can always save up and choose the manual Dobs, however if you feel that you want to make life easier to get you into this hobby, then you may choose between the three types (Push to, Push + and GoTo)

A push to may help you with learning your way around the sky, since it's partly manual. A Push plus requires the use of your phone and is cheaper than a GoTo. A GoTo is fully automated and has the advantage of tracking (not suitable for AP).

these are the links for the posts that helped me decide:

I hope this helps when deciding what to buy. Good Luck