I went there during a hurricane and a volcano eruption so nothing would deter me from going there.   

That was my 5th trip to the Big Island of Hawaii. Since I had been coming there, I had always wanted to visit the top of Mauna Kea, one of the big volcano summits of the islands. On Maui, we ascended Haleakala, 10,023 ft (3,055 m) but our trip to the top of Mauna Kea, 13,803 ft  (4,207 m)  had always been canceled, once because of a hurricane, another time because of a volcano eruption... So I was pretty determined to get up there on this trip.   

The summit is home to major telescopes and is closed shortly after sunset so that scientists can start their observations right away. The only people at the top are not astrophysicists, they are the telescope operators; most scientists are thousands of miles away and only visit once in a while.   

Rental cars should not be driven up there but still, quite a few people do that. The journey uphill is not that hard but is only open to 4WD. But the trip downhill is quite challenging and every week a few cars overheat their breaks instead of driving down in first gear or loose control and end up in the rocks or experience any kind of mechanical failure. That would cost you a lot of money to be towed out here and the rentacar agency will charge you for repairs and the time they cannot rent the car! You'd be better off paying for a tour and get there by bus! That's what I did and the tour came not only with an ascent to the summit for sunset but also a nice stargazing session in one of the darkest place on Earth!   

I know this has nothing to do with diving, so if you're only here for that, you can skip a few paragraphs, but it does have to do with photography...    

At the summit, I was not feeling that good. That was the highest I had ever been, even in the Himalayas, I stayed at about 10,000ft. Anyway, fighting the light headedness, I set up my $9.99 plastic & aluminum tripod with my small Canon G7X MII point and shoot and programmed it for HDR (bracketing +/-1EV) and aperture priority f/8. My wife told me that my altitude sickness was all in my head. That may have been the case, but the proof that I was not feeling all right is in the pictures of that shoot that all came out pretty dramatically bad... Oh well. 

Back at 9,000ft (this is height not depth, so skip this too if you want to go to the juicy diving part), and feeling way better I set up my tripod again but this time set the Canon to full manual 20s exposure, aperture between f/1.8 and f/4.5 and pointed it to the Milky Way that was clearly visible in the sky. While our guide was pointing globular clusters and constellations, I was shooting the stars! 

The first few shots came out pretty bad, with a lot of blur. The Canon has a nice manual focus that is operated by turning the lens, just like in the old days of film (or just old cameras with no autofocus, yes those exist and I had one). The result is visible in real time on-screen and even with just a few dots/stars visible, it was enough to get pretty decent shots. Way better than my first experiments last year in the desert of Joshua Tree... Anyway, I'm posting a few starfield shots below, you'll be the judge. 

BACK TO THE DIVING!

Well it was great, no doubt with that. We dove the Kohala Coast with Mauna Lani Sea Adventure, probably the best kept secret on the island. The dives are all pretty close and we go back ashore for our surface interval for drinks, popcorn and crackers (with the leftover fed to the local birds that flock around the table just for that). The boat only takes six divers and on two of the dives we were only 3 divers and our divemaster. Talk about a personalized experience! The DMs at MLSA have been diving for a long time and they know their spots very well. They're also pretty good at spotting sea life from a hundred yards away (no kidding). We dove very nice caves and a manta cleaning station and we had a real blast, with a pod of dolphin at one of the safety stops that extended my bottom time from 61 to 67 minutes!

Even though I still had my video lights on, I shot my macros with the flash as the pictures from my Cozumel trip the month before showed that it was really better with it than without. For these shots, I alternated Tv 1/125s with Manual f/8 + 1/80-1/125s. I usually got better results with the Manual setting. For the mantas and the light shows as I was able to position myself to get both the mantas and the sunballs in the frame, I usually shot Tv 1/400-1/640s. It's a pain in the neck to go from one setting to another on the Canon, they really designed a camera NOT for divers... Damn I miss my G12 controls. 

I must have still have felt the effect of altitude sickness, despite diving two days after ascending to almost 14,000ft because when I looked at my shots after our first dive, I realized that I was still bracketing... I post-processed these shots for HDR just for fun, and they just ended up like my sunset shots at the summit: crap.