New Telescope: Meade LX90 8" EMC UHC...

[netwolf]

Hi All,

Well I just picked up my LX90 8" today. Went with a good friend of mine who deserve my thanks for taking the time out for me. He also shared showed me his collection of telescopes and accessories, which just shows how far I have to go. Next I have to thank the seller, who has spent many hours on the phone with me insuring I was happy with everything and invited my friend and I into his home to check out the telescope before purchase. All I can say is that I have a new friend in this hobby, and he did me a real bargain.

The scope looks bran new and the optics are very clean, all credit to the owner. My mate and I were going to star test with his artificial star, but we did not bother after seeing how clean it was. The owner did insist we look through it at a terestial target at least as the sun was still up. The image was sharp. Lots of cracks and moss builds up on those telegraph poles. Did a turn on test and everything comes up ok. Did a mock align and goto and slew, all was well.

I will post photos once I set it up. Not today, thought the sky has cleared up. I need to go an buy a battery tomorrow. I was thinking of one from supercheap. Any recommendations.

My good mate has lent me his Neximage (again) so i can get started.
There are still good people in the world who share our hobby and want to see others come forward in there quest. My humble and sincere thanks to you my friends.

The owner is a fellow IIS member and I will leave it to him to reveal himself.
Some of you clever folks will no doubt have already guessed.

Regards
Fahim

[acropolite (Phil)]

Fahim, if you observe within range of a power point get a 12 volt power supply in lieu of (or as well as) a battery (even a 7Ah battery will give several hours of use). Jaycar have some good switch mode supplies at reasonable prices. For what it's worth I don't bother using the LNT or auto align, I level and align north manually then use 2 star alignment, it's more accurate.

[netwolf]

Phil,

Thanks, I dont have LNT and am told its not really of much use. I suppose I should get one of those Long power cords that wind up for, made for outdoor use and 12V supply. I can possibly find a 12V supply amongst my collection of unused computer gear. But what is the amps required?

Anybody used the power tanks sold by supercheap etc used for car jump starting? Or is Jaycar battery better.

I saw a post on LX90 by a user looking to fit 2 6V SLA batteries into the battery compartment. But there was no followup about success or failure on this front. I would prefer an external solution that could be used for other gadgets, even the laptop if need arise. Any suggestions.

Regards
Fahim

[casstony]

I'm sure you'll enjoy the new scope Fahim. I haven't seen a single complaint regarding the figuring of meade's sct optics over the last several years - they seem to be consistently decent - some initial concerns over the LX200R collimation, but that's all.

I use a 17Ah Supercheap jump start battery with the LX90 and it works fine.
The disadvantage with the 240V supply is the possibility of tripping over the lead.

[Omaroo (Chris Malikoff)]

Fahim - congrats on the new scope.

You can buy a GMC 17AH (amp-hour) battery booster/power tank from Bunnings that costs around the $60 mark. I bought one the other day and its been fantastic - better than the larger one I bought from SuperCheap a while back. It comes with a LED front light as well - which you can colourise the lens to red if you wish. The case is well built and if it ever has a problem, GMC comes to your house to replace it as per the Bunnings/GMC warranty.

I also run a separate 17AH sealed battery from Jaycar - but the combined price of the battery and the appropriate charger is more than the whole GMC unit - and then you have to put it in a case or something.

Just my 2c

Originally Posted by netwolf

Phil,

Thanks, I dont have LNT and am told its not really of much use. I suppose I should get one of those Long power cords that wind up for, made for outdoor use and 12V supply. I can possibly find a 12V supply amongst my collection of unused computer gear. But what is the amps required?

Anybody used the power tanks sold by supercheap etc used for car jump starting? Or is Jaycar battery better.

I saw a post on LX90 by a user looking to fit 2 6V SLA batteries into the battery compartment. But there was no followup about success or failure on this front. I would prefer an external solution that could be used for other gadgets, even the laptop if need arise. Any suggestions.

Regards
Fahim

[wavelandscott (Scott)]

Congratulations on the new scope!

I hope that you get much enjoyment from it!

[netwolf]

Thanks Guys,

I just popped into bunnings it was 70$ and the warranty is a unit replacement for 2 years but there is a small freight charge or you take it into the place of purchase. My mate got one to. My friend got one for his LX200R 10" and it ran 2 days without breaking a sweat. And now the clouds are rolling in.... I hope it clears up soon.

Next I need to get one of those plastic boxes to store it in. Fortunately the previous owner had the orginal box with the foam inserts. So I can reuse these. But i forgot to measure the box this morning, So i did not grab one at lunch time. Can anyone recommend a box size? I have seen them at the warehouse with wheels on them. Are these any good for indoor storage.

Regards
Fahim

[netwolf]

First light tonight, and before I started I first flashed the firmware. It was 26E, got it up to the 43Ed firmware patched to 44dd (usual patch from LX90 groups).
I did not count on it taking so long to to the flash, I wish there was a way I could do this without the whole scope. I mean is there no way to just connect the Autostar to the PC and flash it.. I guess it needs to get power via the scope. Is there a standalone power up option..

Anyway this gave the Scope time to cool down a bit. Ther was some light cloud rolling and it covered the moon, still I could see the moon through it and it was stunning. I Aligned on Sirus and Beatlejuice and it placed the moon in the FOV (a little off center). But then I did a very rough level and north alignment. I did use the STargps Redirect utility to connect my bluetooth GPS via the laptop with the HC, and though it connected and started sending through information. I can not be sure it did anything as I could not find anything on the HC. Did a Goto to the Horsehead and it was way off. So went back to Sirus, which was on the Edge of the FOV, centred it. Quickly read the online manual to work out how to do a sync. Done. Now I did a quick star test, looked good to me but the outside two rings were a bit "furry" the inner rings were perfect and concentric. This was with 5x barlow in there, I noted that Sirus would not focus to a point but rather it focused to a small dot with concentric circles. I guess I just need to focus better.

I went across to Procyon and noted it was very dull, so I check the mirror and it was getting a little foggy. Used my red light torch and I saw a bit of fog. And dust I had not noticed before. I decided to call it for the time being, a bit scared off by the fogg on the corrector I guess. Got it back in and noticed it was still there, but by the time i grabbed the camera and took a few shots it was gone. Hmm and it has cleared up outside. Darn it.. Saturn's just coming up.

Goto is sweet, tracking is sweet. Left it on Sirus for 20mins and it tracked perfectly. Fog/Dew not sure what the heck happened, I went out at 8:30pm and was only out till about 10pm. I thought dew did not occur till later on in the night..

Here are some pics one to show the dust on the corrector ( i need a blower) is this normal?

Regards
Fahim

[jjjnettie (Jeanette)]

Lucky lucky man. I hope that you enjoy your new purchase.

[AndrewJ]

Gday Fahim
Re

I wish there was a way I could do this without the whole scope. I mean is there no way to just connect the Autostar to the PC and flash it..

Weasners site is yr source for all "Autostar specific" questions.
Theres a lot of info there, but if you go to
http://www.weasner.com/etx/autostar_info.html
and look at the "Cable and power information" section
you will see quite a few references to how to make a power box.
( Just an RJ45 connector with a 12V line and a ground line. )

With the 497 Autostars, the CPU is in the HBx, so as long as you make a ( correctly wired ) power supply using the RJ45 connector, it will come to life and initialise far enough to allow you to update normally.
This will not work for the ASII handboxes used in the GPS/RCX scopes.

Disclaimer
YOU must absolutely ensure you get the polarity correct.
If you are not comfortable doing this, dont do it,
the HBx has no reverse polarity protection.

Andrew

[netwolf]

Thanks Andrew, I think I can manage that. I also found some of your posts about a PWM dew heater on the forums. I am thinking of getting the Astrozap with heater. And maybe try my hand at building a PWM controller, but I have read that this should be powered from a seperate source to the main telescope power source. Is this correct? I believe it has to do with back interference.

I have worked with all this at uni but i am not very good at the soldering and PCB part, I used to work out the theory/design and let my partners deal with the wire up. Is there an off the shelf project kit that I could use, and program to my needs. Preferably something that can be programmed via a simple PC link, not requiring a separate reprogrammer etc.

Regards

[AndrewJ]

Gday Fahim

but I have read that this should be powered from a seperate source to the main telescope power source. Is this correct? I believe it has to do with back interference

.

The above is good practice, but if you have a really large battery, it probably wont hurt to run both heater and scope off it.
( As long as the supply lines all terminate at the battery terminals )
Preferably though, have a dedicated source for yr scope/cameras etc
and a seperate battery for a dewheater ( if its PWM ).

Is there an off the shelf project kit that I could use, and program to my needs. Preferably something that can be programmed via a simple PC link, not requiring a separate reprogrammer etc.

There are no ( cheap ) off the shelf controllers i know of that are programmable. However, i have made various units up that are just std passive ( ie controlled by a pot ) or PIC based ( thermostatic control )
In the PIC variety, there are true PICs ( that require coding in assembler, or some form of compiler ) and also need a dedicated programmer
or, for simple stuff, there is a brilliant little system called PICAXE.
This is readily available in OZ,
The programming software is free, and the hardware for programming is two resistors and a diode. It runs off a std serial port and is very easy to use.
If all you want is a simple thermostic unit, you could probably even build it on breadboard.

Andrew

[netwolf]

Ah the good old trusty breadboard.. I have seen this PICAXE mentioned before on a Australian website somewhere. If I recall correctly Bird used it for his temperature logger.

Have looked around and there seem to be 3 systems on the market that I can find. Kendrick passive and active controllers, Dewbuster, and Thousand Oaks System (looks passive). The cheapest avalable in OZ is Thousand oaks system. But am not sure which is the best. Lots of good reviews on the dewbuster/dew-not combination indicating low power usage.

Its cloudy outside and hence all this ramble..

Regards
Fahim

[netwolf]

Just saw this on another thread by Al, easy enough for me to make this one.
http://www.iceinspace.com.au/index.p...63,285,0,0,1,0

However I assume PWM will mean interference if designed incorrectly. I have read the Kendrick Mark IV is designed to prevent interference. Possibly they are using EMI suppression techniques in the chassis.

Regards

[AndrewJ]

Gday Fahim

Lots of good reviews on the dewbuster/dew-not combination indicating low power usage.

The PICAXE is a true microprocessor, hence can read temp sensors and adjust output power accordingly.
This is the method the Dewbuster and later model Kendricks use.
Ie the power only comes on for as long as reqd, then turns itself off.
As such, they are very efficient.

Just saw this on another thread by Al, easy enough for me to make this one.

Ahhh, the Dickies Jaycar special. This unit operates at a high frequency
( around 2KHz IIRC ) and also uses a chip that isnt really suited to doing what we want. It works, but its overkill, and is still manual set.
I have attached a piccy of one of the simplest ones i use.
Does the same thing and almost fits in a matchbox

With this, you can set the freq to anything you want, and get true, proportional power control.
However, it also is still manually controlled, so will not be anywhere near as efficient as a controlled unit.

However I assume PWM will mean interference if designed incorrectly. I have read the Kendrick Mark IV is designed to prevent interference. Possibly they are using EMI suppression techniques in the chassis.

Depends on what you mean by interference.
I have tested a new Kendrick, and it was running at about 50Hz
( vs 5 on/off per minute in the old version )
There are two main forms of interference that affect us
1) Back transmission via the supply line
2) RFI from the unit/wires

1) Can be reduced by good filtering etc on the input to the controller
however
2) Is independent of the controller
The power wires going from the controller to the heater element
( and the element itself if its a wire based one ) all act as ariels to radiate RFI.
You can easily test this by putting a detuned AM radio near yr unit.
I get a noticable RFI from all my units, but none has upset my Autostar to date. The only way to avoid this is to use a very low freq PWM.
( Or find a way of totally shielding yr wires and heater elements )

Andrew